Optical and electric signals transmission apparatus, optical and electric signals transmission system, and electronic equipment using such a system

ABSTRACT

An optical and electric signals transmission apparatus includes a receptacle having a light-receiving element and/or a light-receiving element and electrical connecting terminals, a plug having electrical connecting terminals to establish electrical coupling with the receptacle and optical coupling with the light-emitting element and/or the light-receiving element, an electric signal transmission line, and an optical signal transmission line. The receptacle has a fitting recess, and when the plug is fitted in the fitting recess in a direction substantially perpendicular to the optical axis of the light-emitting element or the light-receiving element, the optical coupling, the electrical coupling, and engagement of the receptacle with the plug are established at a location where the fitting recess and the plug are adjacent to each other.

This nonprovisional application claims priority under 35 U.S.C. §119(a)on Patent Application No(s). 2007-125466 filed in Japan on May 10, 2007,the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an optical and electric signalstransmission apparatus, an optical and electric signals transmissionsystem, and electronic equipment using the optical and electric signalstransmission system, which perform transmission of optical and electricsignals including high-speed optical signal.

Conventional optical and electric signals transmission apparatusestransmitting both of an optical signal and an electric signal include a“plug and jack type optical and electric common use transmission device”disclosed in JP 6-140106 A (patent document 1). FIG. 41 is a front viewof a receptacle (holder) 1 of the plug and jack type optical andelectric common use transmission device, and FIG. 42 is a side view ofthe holder. FIG. 43 is a side view of an optical plug 2 which isattached to the holder 1.

In the plug and jack type optical and electric common use transmissiondevice disclosed in the patent document 1, an optical transmittingdevice 3 or an optical receiving device 4 is accommodated in the holder1 equipped with a mechanism of fitting and holding the optical plug 2having an optical fiber cable 5. A hole for fitting and holding theoptical plug 2 is formed in the holder 1 along the optical axis of theholder 1. The optical plug 2 is inserted along the optical axis in thehole 6 of the holder 1 and is thereby fitted and held at a predeterminedposition, so that optical coupling for optical signal transmissionbecomes possible.

Lead terminals 7 in FIGS. 41 and 42 are signal input terminals for theoptical transmitting device 3. Lead terminals 8 are output terminals forthe optical receiving device 3. The reference numeral 9 denotes leadterminals for electric signal transmission.

FIG. 44 is a cross-sectional view showing the state that the opticalplug 2 has been inserted in the holder 1. FIG. 45 is a cross-sectionalview showing the state that an electric plug 10 has been inserted in theholder 1 and electric signal transmission is possible. In FIG. 45,electrodes 11 a, 11 b, and 11 c of the electric plug 10 are electricallyconnected with corresponding connecting terminals 9 a, 9 b, and 9 c oflead terminals 9. As described above, in the plug and jack type opticaland electric common use transmission device disclosed in the patentdocument 1, optical signal transmission is possible when the opticalplug 2 has been inserted in the holder 1, and electric signaltransmission is possible when the electric plug 10 has been inserted inthe holder 1.

Furthermore, conventional optical and electric signals transmissionapparatuses include a “connecting device” disclosed in JP 62-193208 U(patent document 2). FIG. 46 shows a male connecting component (plug) 15and a female connecting component (jack) 16 of this connecting device.Both of an optical signal and an electric signal are transmitted byinserting a connecting projection (inserted portion) 17 of the maleconnecting component 15 into a socket 18 of the female connectingcomponent 16.

As a cable to be connected, a composite cord constituted by an opticalfiber 19 and a plurality of electric signal transmission wires is used,and the connecting projection 17 which contains the optical fiber 19along the axis and has a plurality of conductors 20, 21, and 22 arrangedin the axis direction on the periphery is mounted on an end portion ofthe composite cord. The female connecting component 16 has a shieldingconductor 23 which is electrically connected to the first conductor 20of the connecting projection 17 when the connecting projection 17 isinserted in the socket 18, an Lch conductor 24 which is electricallyconnected to the second conductor 21 of the connecting projection 17when the connecting projection 17 has been inserted in the socket 18, anRch conductor 25 which is electrically connected to the third conductor22 of the connecting projection 17 when the connecting projection 17 hasbeen inserted in the socket 18, and an optical element 26 which isoptically coupled to an end portion 19 a of the optical fiber 19 whenthe connecting projection 17 has been inserted in the socket 18.

According to the connecting device disclosed in the patent document 1,it becomes possible to select both or either of optical signaltransmission and electric signal transmission. However, it is notdescribed that the connecting device is used along with a small singlehead electric plug, and the connecting device is a connector usedexclusively for optical and electric signals transmission.

Furthermore, conventional optical and electric signals transmissionapparatuses include a “plug-jack type connector” disclosed in JP 61-108U (patent document 3). FIG. 47 is a cross-sectional view showing theconfiguration of the plug of the plug-jack type connector. The plug hasterminal portions for electrical connection 31 and 32, and atransmitting optical fiber 33 and a receiving optical fiber 34 whichpenetrate the terminal portions for electrical connection 31 and 32 toan end face of the plug. FIG. 48 shows the sate that the plug has beenfitted in the jack. In FIG. 48, the terminal portion for electricalconnection 31 of the plug is connected with a conductor for power supply36 of the jack 35, and the terminal for electrical connection 32 isconnected with a grounding conductor 37 of the jack 35. In addition, thejack 35 has a light-emitting element 38 and a light-receiving element39, which are optically coupled with a transmitting optical fiber 33 anda receiving optical fiber 34, respectively, to perform optical signaltransmission.

However, the conventional optical and electric signals transmissionapparatuses have the following problems. The plug and jack type opticaland electric common use transmission device disclosed in the patentdocument 1 is able to transmit an optical signal and an electric signal,but is not able to transmit an optical signal and an electric signal atthe same time as described above. Furthermore, the plug and jack typeoptical and electric common use transmission device is structured insuch a manner that the optical plug 2 is covered with the holder 1,which constitutes a large restriction on miniaturization of the device.In addition, the optical plug 2 must be moved along the optical axiswhen the optical plug 2 is inserted in and extracted from the holder 1,so that a region for the insertion and extraction having a length longerthan the length of the optical plug 2 must be kept in front of theinsertion opening of the holder 1 on a printed circuit board on whichthe holder 1 is mounted. Thus, any component can not be disposed in theregion on the printed circuit board.

From the reason stated above, the plug and jack type optical andelectric common use transmission device disclosed in the patent document1 has a problem that it is unsuitable for being mounted on portableequipment which is going to be reduced in size and thickness.

Furthermore, it has been realized by the connecting device disclosed inthe patent document 2 that an optical signal and an electric signal aretransmitted by a small and thin device. However, in the patent document2, only a mechanism realizing electrical contacts is disclosed, and aprecision positioning mechanism and a fitting and holding mechanism forthe plug and jack necessary for optical coupling are not described. Inaddition, like the conventional optical and electric signalstransmission apparatus disclosed in the patent document 1, theconnecting device is structured in such a manner that the connectingprojection 17 is covered with the female connecting component 16, whichconstitutes a large restriction on miniaturization of the device. Inaddition, a region for insertion and extraction having a length longerthan the length of the connecting projection 17 must be kept in front ofthe socket 18 on a printed circuit board on which the female connectingcomponent 16 is mounted. Thus, no component can be disposed in theregion on the printed circuit board.

Furthermore, in the plug-jack type connector disclosed in the patentdocument 3, a hybrid plug and jack is provided for an optical signal andan electrical signal, and two-way communication by an optical signal andan electric signal is realized. However, the optical plug is structuredso as to partially have metal blades for electrical contacts and coveredwith the jack 35, like the conventional optical and electric signalstransmission apparatus disclosed in the patent document 1, whichconstitutes a large restriction on miniaturization of the connector. Inaddition, a region for the insertion and extraction of the plug having alength larger than the length of the plug must be kept in front of theplug insertion opening of the jack 35 on a printed circuit board onwhich the jack 35 is mounted. Thus, no component can be disposed in theregion on the printed circuit board.

From the reason stated above, the connecting device disclosed in thepatent document 2 or the plug-jack type connector disclosed in thepatent document 3 also has a problem that it is unsuitable for beingmounted on portable equipment which is going to be reduced in size andthickness.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide an opticaland electric signals transmission apparatus, an optical and electricsignals transmission system, and electronic equipment using an opticaland electric signals transmission system, which are small and thin andare able to transmit an optical signal and an electric signal at thesame time without needing a dead area for insertion and extraction of anoptical plug on a printed circuit board.

There is provided, according to an aspect of the present invention, anoptical and electric signals transmission apparatus comprising:

a receptacle for optical and electric signals transmission whichaccommodates and holds at least any one of an optical transmittingdevice including a light-emitting element and an optical receivingdevice including a light-receiving element and a signal processingcircuit processing a signal from the light-receiving element, and has anelectrical connecting terminal;

a plug for optical and electric signals transmission which has anelectrical connecting terminal to be connected to the electricalconnecting terminal of the receptacle and is adapted to be inserted inthe receptacle to establish electrical coupling with the receptacleand/or optical coupling with at least any one of the light-emittingelement and the light-receiving element and perform optical and electricsignals transmission with the receptacle;

an electric signal transmission line, an end of which is connected withthe electrical connecting terminal of the plug; and

an optical signal transmission line, an end portion of which is mountedto the plug,

wherein the receptacle has a fitting recess in which the plug is to befitted when inserted in the receptacle from a direction substantiallyperpendicular to an optical axis of the light-emitting element or thelight-receiving element;

wherein when the plug is fitted in the fitting recess of the receptacle,the optical coupling, the electrical coupling, and engagement of thereceptacle with the plug are established at a location where the fittingrecess and the plug are adjacent to each other; and

wherein one-way or two-way optical communication and one-way or two-wayelectrical communication are performed between the receptacle and theplug fitted in the fitting recess.

According to the above configuration, when the plug is inserted in adirection substantially perpendicular to the optical axis of thelight-emitting element or the light-receiving element and fitted in thefitting recess of the receptacle, optical coupling between thereceptacle and the plug, electrical coupling between the light-emittingelement and/or the light-receiving element and the plug, and engagementof the receptacle with the plug are established at a location where thefitting recess and the plug are adjacent to each other. Thus, it is notany more necessary to keep a region for extraction from and insertioninto the receptacle of the plug performed along the optical axisdirection, near the receptacle. For this reason, other components may bemounted in such a region on a substrate on which the receptacle ismounted.

In other words, the optical and electric signals transmission apparatusperforming one-way or two-way optical communication and one-way ortwo-way electrical communication at the same time is allowed to bereduced in size.

In addition, the receptacle is not required to cover or enclose theinsertion side of the plug after the plug has been fit in the fittingrecess. Thus, the optical and electric signals transmission apparatusperforming one-way or two-way optical communication and one-way ortwo-way electrical communication at the same time can be reduced inthickness.

In one embodiment, the receptacle accommodates and holds the opticaltransmitting device or the optical receiving device. And, the plugestablishes optical coupling with the light-emitting element or thelight-receiving element, and one-way optical communication and one-wayor two-way electrical communication are performed between the receptacleand the plug.

According to this embodiment, the optical and electric signalstransmission apparatus performing one-way optical communication andone-way or two-way electrical communication at the same time is allowedto be reduced in size and thickness.

In one embodiment, the receptacle accommodates and holds the opticaltransmitting device or the optical receiving device. And, the plugestablishes optical coupling with the light-emitting element or thelight-receiving element, and two-way optical communication and one-wayor two-way electrical communication are performed between the receptacleand the plug.

According to the above configuration, the optical and electric signalstransmission apparatus performing two-way optical communication andone-way or two-way electrical communication at the same time is allowedto reduced in size and thickness.

In one embodiment, the optical signal transmission line is an opticalfiber cable. And, when the plug is fitted in the fitting recess of thereceptacle, the optical coupling is established between an end face ofthe optical fiber cable and the light-emitting element or thelight-receiving element.

According to this embodiment, the one-way optical signal transmissionline is constituted by an optical fiber cable, so that one-wayhigh-speed optical signal transmission and two-way or one-way electricsignal transmission can be realized by a smaller, thinner, andspace-saving optical and electric signals transmission apparatus.

In one embodiment, the optical signal transmission line comprises a pairof optical fiber cables, one for transmission and the other forreception, and when the plug is fitted in the fitting recess of thereceptacle, the optical coupling is established between an end face ofthe optical fiber cable for transmission and the light-emitting element,while the optical coupling is established between an end face of theoptical fiber cable for reception and the light-receiving element.

According to this embodiment, the two-way optical signal transmissionline is constituted by optical fiber cables, so that two-way high-speedoptical signal transmission and two-way or one-way electric signaltransmission can be realized by a smaller, thinner, and space-savingoptical and electric signals transmission apparatus.

In one embodiment, the electric signal transmission line is a flexiblesubstrate including a metal wire, and an end portion of the flexiblesubstrate is mounted on a periphery of the plug. The electricalconnecting terminal of the plug to be connected to the electricalconnecting terminal of the receptacle is formed on a surface of theflexible substrate mounted on the periphery of the plug and is connectedwith the metal wire in the flexible substrate.

According to this embodiment, the electric signal transmission line isconstituted by a flexible substrate having a metal wire, and theelectrical coupling with the electrical connecting terminal of thereceptacle is established through the electrical connecting terminalformed on the surface of the flexible substrate mounted on and fixed tothe periphery of the plug, so that it becomes unnecessary to connect theelectrical connecting terminal to the electric signal transmission lineinside the plug, and thereby the structure of the plug can be simplifiedand a plug for optical and electric signals transmission which is smalland thin can be realized.

In one embodiment, the electrical connecting terminal of the receptacleis provided on an inner side surface of the fitting recess, and theelectrical connecting terminal formed on the surface of the flexiblesubstrate is disposed on a side surface of the plug.

According to this embodiment, the electrical connecting terminal of thereceptacle and the electrical connecting terminal of the plug, betweenwhich the electrical coupling is to be established, are provided on aninner side surface of the fitting recess and a side surface of the plug.Thus, a number of electrical connecting terminals can be provided on thesmall receptacle and plug for optical and electric signals transmission.

In one embodiment, the electrical connecting terminal of the receptacleis provided on an inner bottom face of the fitting recess, and theelectrical connecting terminal formed on the surface of the flexiblesubstrate is disposed on a bottom face of the plug.

According to this embodiment, the electrical connecting terminal of thereceptacle and the electrical connecting terminal of the plug betweenwhich the electrical coupling is established are provided on the innerbottom face of the fitting recess and the bottom face of the plug. Thus,the direction of fitting of the plug to the receptacle can be madesubstantially identical to the direction of the electrical coupling. Forthis reason, the electrical connecting terminal structure of the plugcan be simplified, and a plug for optical and electric signalstransmission which is small, thin, and space-saving can be thusrealized.

In one embodiment, the electrical connecting terminal of the receptacleincludes electrical connecting terminals provided on an inner sidesurface and an inner bottom face of the fitting recess. Also, theflexible substrate of which the end portion is mounted on the peripheryof the plug is constituted by two flexible substrates on which theelectrical connecting terminals are formed. The electrical connectingterminal of one of the two flexible substrates is disposed on a sidesurface of the plug, while the electrical connecting terminal of theother flexible substrate is disposed on a bottom face of the plug.

According to this embodiment, the electrical coupling is established bythe electrical connecting terminals which are simply structured and theelectrical connecting terminals which can be arranged a lot. Thus, aplug for optical and electric signals transmission which is small andthin and has a lot of electrical connecting terminals can be realized.

In one embodiment, the electrical connecting terminal of the receptacleincludes electrical connecting terminals provided on an inner sidesurface and an inner bottom face of the fitting recess, and theelectrical connecting terminal formed on the surface of the flexiblesubstrate includes electrical connecting terminals disposed on a sidesurface and a bottom face of the plug.

According to this embodiment, the electrical connecting terminals whichare simply structured and the electrical connecting terminals which canbe arranged a lot are formed on the same flexible substrate. Thus, theplug for optical and electric signals transmission, which is small andthin and has as many electrical connecting terminals as possible, can befurther reduced in thickness.

In one embodiment, the electric signal transmission line is a coaxialcable including a copper wire, and the electrical connecting terminal ofthe plug connected to the electrical connecting terminal of thereceptacle is provided on the periphery of the plug and soldered to thecopper wire.

According to this embodiment, the copper wire of the coaxial cable issoldered to the electrical connecting terminal of the plug. Thus, anelectric signal transmission line which is not limited in bendingdirection can be realized.

In one embodiment, the light-emitting element of the opticaltransmitting device and the light-receiving element and signalprocessing circuit of the optical receiving device are mounted on a leadframe and sealed with resin.

According to this embodiment, a receptacle which is small, thin,space-saving, and of a lead type can be realized.

In one embodiment, the light-emitting element of the opticaltransmitting device and the light-receiving element and signalprocessing circuit of the optical receiving device are mounted on arigid printed circuit board and sealed with resin.

According to this embodiment, a receptacle which is small, thin,space-saving, and of a surface-mounted type can be realized.

In one embodiment, of regions of the bottom face of the receptacle,which is a surface opposite to a surface in which the fitting recess isformed, an outer region outside of a region opposite to the fittingrecess is lower than the region opposite to the fitting recess by apredetermined height such that the region opposite to the fitting recessis made a protrusion and that the outer region serves as a mountingsurface for a substrate. And, the substrate on which the receptacle ismounted has a fitting portion which has a shape corresponding to theshape of the protrusion of the receptacle so that the protrusion isfitted in the fitting portion in order that the mounting surface of thereceptacle comes into contact with a surface of the substrate when theprotrusion of the receptacle is fitted in the fitting portion, whereby amounting height of the receptacle to the substrate is made low and amounting position of the receptacle to the substrate is fixed.

According to this embodiment, the mounting surface of the receptacle forthe substrate is positioned higher than the bottom face. This makes itpossible to realize an optical and electric signals transmissionapparatus that has the receptacle mounted to the substrate at a reducedheight (i.e., a small mounting height) and that is easy to besurface-mounted.

In one embodiment, the optical transmitting device and the opticalreceiving device are separated from each other.

According to this embodiment, the optical transmitting device and theoptical receiving device are formed to be separated from each other, sothat at a production stage where the yield of one of the light-emittingelement or the light-receiving element is lower than the yield of theother, the production process can be efficiently performed withoutinfluence of the lower degree of the yield upon the higher degree of theyield.

In one embodiment, the optical transmitting device and the opticalreceiving device are formed in one piece to constitute an opticaltransmitting and receiving device, and a groove for separating thelight-emitting element and the light-receiving element from each otheris provided between the optical receiving device and the opticaltransmitting device of the optical transmitting and receiving device.

According to this embodiment, the optical transmitting device and theoptical receiving device are formed in one piece to constitute anoptical transmitting and receiving device, so that the optical andelectric signals transmission apparatus can be assembled easily and thusmanufactured efficiently at low cost.

In one embodiment, the optical signal transmission line is an opticalwaveguide, and when the plug is fitted in the fitting recess of thereceptacle, the optical coupling is established between an end face ofthe optical waveguide and the light-emitting element or thelight-receiving element.

According to this embodiment, the optical signal transmission line isconstituted by an optical waveguide. Thus, the optical coupling portionof the receptacle and the plug can be made smaller and this contributesto further reduction in size and thickness of the optical and electricsignals transmission apparatus performing one-way high-speed opticalsignal transmission and two-way or one-way electric signal transmission.As a result, a space-saving apparatus is realized.

In one embodiment, the optical signal transmission line comprises a pairof optical waveguides, one for transmission and the other for reception.And, when the plug is fitted in the fitting recess of the receptacle,the optical coupling is established between an end face of the opticalwaveguide for transmission and the light-emitting element, while theoptical coupling is established between an end face of the opticalwaveguide for reception and the light-receiving element.

According to this embodiment, the optical signal transmission line isconstituted by a pair of an optical waveguide for transmission and anoptical waveguide for reception. Thus, the optical coupling portion ofthe receptacle and the plug can be made smaller and the optical andelectric signals transmission apparatus performing two-way high-speedoptical signal transmission and two-way or one-way electric signaltransmission can be reduced in size and thickness to be space-saving.

In one embodiment, the electric signal transmission line is a flexiblesubstrate including a metal pattern, and the optical waveguide which isthe optical signal transmission line is formed in and held by theflexible substrate. The flexible substrate constitutes an optical andelectric signals transmission line.

According to this embodiment, the optical waveguide which is the opticalsignal transmission line is formed in and held by the flexible substrateincluding the metal pattern which is the electric signal transmissionline. This means that the optical waveguide shares the flexiblesubstrate with the metal pattern. Thus, a plug, which is small, thin andeasy to assemble, is obtained.

In one embodiment, the plug mounted, on its periphery, with the endportion of the flexible substrate having the electrical connectingterminal on its surface is formed in one piece by insert-molding theflexible substrate having the electrical connecting terminal on itssurface and a resin plug body together.

According to this embodiment, the flexible substrate having theelectrical connecting terminal on its surface and the resin plug bodyare formed together by insert-molding. Thus, the process of assemblingthe plug is simplified and a small and thin optical and electric signalstransmission apparatus which is excellent in productivity is obtainable.

In one embodiment, the plug having the electrical connecting terminal onits surface is formed in one piece by insert-molding the electricalconnecting terminal and the resin plug body together, and the copperwire of the coaxial cable is soldered to the electrical connectingterminal which is integrally formed with the plug body.

According to this embodiment, after the electrical connecting terminalsand the resin plug body have been insert-molded in one piece, the copperwire of the coaxial cable is soldered to the electrical connectingterminal. Thus, a small and thin optical and electric signalstransmission apparatus which is excellent in flexibility is easilyobtainable.

In one embodiment, the optical signal transmission line is an opticalwaveguide. And, when the plug is fitted in the fitting recess of thereceptacle, the optical coupling is established between an end face ofthe optical waveguide and the light-emitting element or thelight-receiving element.

According to this embodiment, the process of assembling the plug can besimplified, and a small and thin optical and electric signalstransmission apparatus which is excellent in productivity is obtainable.

In one embodiment, the light-emitting element is a surface emittinglaser.

According to this embodiment, the light-emitting element is constitutedby a surface emitting laser, which simplifies the structure of theoptical transmitting device. Thus, a small, thin, and low-cost opticaland electric signals transmission apparatus is obtainable.

According to another aspect of the present invention, there is providedan optical and electric signals transmission system comprising a firstoptical and electric signals transmission apparatus and a second opticaland electric signals transmission apparatus, each of the first opticaland electric signals transmission apparatus and the second optical andelectric signals transmission apparatus consisting of the describedoptical and electric signals transmission apparatus according to thepresent invention. In this system, the electric signal transmission lineof the first optical and electric signals transmission apparatus and theelectric signal transmission line of the second optical and electricsignals transmission apparatus are electrically coupled with each other,while the optical signal transmission line of the first optical andelectric signals transmission apparatus and the optical signaltransmission line of the second optical and electric signalstransmission apparatus are optically coupled with each other. The firstoptical and electric signals transmission apparatus includes at leastthe optical transmitting device and a drive control circuit driving andcontrolling the light-emitting element of the optical transmittingdevice. The second optical and electric signals transmission apparatusincludes at least the optical receiving device, a receiving circuitextracting a receiving signal from a light-receiving signal obtained bythe signal processing circuit of the optical receiving device, and areceiving level detecting circuit detecting the level of the receivingsignal. The second optical and electric signals transmission apparatusis configured to receive an optical signal transmitted from the firstoptical and electric signals transmission apparatus through the opticalsignal transmission line and transmit to the first optical and electricsignals transmission apparatus through the electric signal transmissionline an electric signal representing the level of the receiving signalextracted from the light-receiving signal, which is obtained byreceiving the optical signal. And, the drive control circuit of thefirst optical and electric signals transmission apparatus controls thelight-emitting element in such a manner that an amount of light emittedby the light-emitting element becomes optimum, on the basis of the levelof the receiving signal represented by the electric signal transmittedfrom the second optical and electric signals transmission apparatus.

According to this configuration, the drive control circuit of the firstoptical and electric signals transmission apparatus drives and controlsthe light-emitting element in such a manner that the amount of lightemitted by the light-emitting element becomes optimum, on the basis ofthe level of a receiving signal represented by an electric signaltransmitted from the second optical and electric signals transmissionapparatus. Thus, an optical and electric signals transmission system isachievable which is able to obtain an optimum level optical signal withrelative ease and which is capable of steady high-speed opticaltransmission. In addition, the optical and electric signals transmissionapparatus of the present invention which can be reduced in size andthickness is used as the first optical and electric signals transmissionapparatus and the second optical and electric signals transmissionapparatus. Thus, an optical and electric signals transmission systemwhich is small, thin, and suitable for mounting on portable equipment isachievable.

In one embodiment, each of the first optical and electric signalstransmission apparatus and the second optical and electric signalstransmission apparatus includes the optical transmitting device, theoptical receiving device, the drive control circuit driving andcontrolling the light-emitting element of the optical transmittingdevice, the receiving circuit extracting a receiving signal from alight-receiving signal obtained by the signal processing circuit of theoptical receiving device, and the receiving level detecting circuitdetecting the level of the receiving signal. One of the first opticaland electric signals transmission apparatus or the second optical andelectric signals transmission apparatus that has received an opticalsignal transmitted through the optical signal transmission linetransmits an electric signal representing the level of the receivingsignal based on the obtained light-receiving signal to the other opticaland electric signals transmission apparatus through the electric signaltransmission line. One of the first optical and electric signalstransmission apparatus or the second optical and electric signalstransmission apparatus that has received the electric signalrepresenting the level of the receiving signal transmitted through theelectric signal transmission line controls the light-emitting element bythe drive control circuit in such a manner that an amount of lightemitted by the light-emitting element becomes optimum, on the basis ofthe level of the receiving signal represented by the electric signal.

According to this configuration, the optical and electric signalstransmission system is capable of performing steady two-way high-speedoptical transmission, and is small, thin, and suitable for mounting onportable equipment.

In one embodiment, the electric signal transmitted from the secondoptical and electric signals transmission apparatus to the first opticaland electric signals transmission apparatus through the electric signaltransmission line is an analog electric signal.

According to this embodiment, the electric signal representing the levelof the receiving signal is an analog electric signal. Thus, the level ofthe received optical signal can be amplified and directly fed back tothe first optical and electric signals transmission apparatus, so thatthe first optical and electric signals transmission apparatus is able todirectly drive and control the light-emitting element by the drivecontrol circuit on the basis of the fed back analog signal. As a result,an optical and electric signals transmission system which is able toperform steady high-speed optical transmission with a simple circuit isachievable.

In one embodiment, the drive control circuit of the first optical andelectric signals transmission apparatus includes an analog processingcircuit setting a drive current for the light-emitting element on thebasis of the analog electric signal transmitted from the second opticaland electric signals transmission apparatus.

According to this embodiment, the analog processing circuit sets a drivecurrent for the light-emitting element on the basis of an analogelectric signal. An optical and electric signals transmission systemwhich is able to perform steady high-speed optical transmission with asimple circuit is thus achievable.

In one embodiment, the electric signal transmitted from the secondoptical and electric signals transmission apparatus to the first opticaland electric signals transmission apparatus through the electric signaltransmission line is a digital electric signal.

According to this embodiment, the electric signal representing the levelof the receiving signal is a digital electric signal. Thus, the opticaland electric signals transmission system is able to transmit and receivethe level of the receiving signal using a steady digital electric signaland perform steady high-speed optical transmission.

In one embodiment, the first optical and electric signals transmissionapparatus includes a D/A converter converting the digital electricsignal transmitted from the second optical and electric signalstransmission apparatus to an analog electric signal. And, the drivecontrol circuit of the first optical and electric signals transmissionapparatus sets a drive current for the light-emitting element on thebasis of the analog electric signal obtained by the D/A converter.

According to this embodiment, the digital electric signal which has beentransmitted is converted to an analog electric signal by the D/Aconverter, and then a drive current for the light-emitting element isset based on the analog electric signal. Thus, an optical and electricsignals transmission system which is able to perform steady high-speedoptical transmission with a simple circuit is achievable.

In one embodiment, the optical and electric signals transmission systemfurther includes a microcomputer which receives the digital electricsignal transmitted from the second optical and electric signalstransmission apparatus, obtains using an internal correlation table adigital electric signal representing such a drive current for thelight-emitting element that allows the amount of light emitted by thelight-emitting element to be optimum, converts the digital electricsignal to an analog electric signal by an internal D/A converter, andsends out the analog electric signal to the drive control circuit of thefirst optical and electric signals transmission apparatus. The drivecontrol circuit of the first optical and electric signals transmissionapparatus sets the drive current for the light-emitting element on thebasis of the analog electric signal sent out from the microcomputer.

According to this embodiment, the microcomputer obtains from thereceived digital electric signal an analog electric signal representinga drive current for the light-emitting element allowing an optimumamount of light to be emitted by the light-emitting element, and a drivecurrent for the light-emitting element is set based on the analogelectric signal. Thus, the first optical and electric signalstransmission apparatus dose not need to set a drive current for thelight-emitting element in such a manner that the amount of light emittedby the light-emitting element becomes optimum. Thus, the optical andelectric signals transmission system is able to perform steadyhigh-speed optical transmission with the simple circuit configuration ofthe first optical and electric signals transmission apparatus.

In one embodiment, the digital electric signal transmitted from thesecond optical and electric signals transmission apparatus to the firstoptical and electric signals transmission apparatus is a serial signal.

According to this embodiment, the digital electric signal transmittedfrom the second optical and electric signals transmission apparatus tothe first optical and electric signals transmission apparatus is aserial signal. Thus, the number of the electric signal transmissionlines between the first optical and electric signals transmissionapparatus and the second optical and electric signals transmissionapparatus may be one, and a smaller and simpler optical and electricsignals transmission system is achievable.

According to another aspect of the present invention, there is providedan electronic equipment comprising a first housing having a displayunit, and a second housing connected with the first housing so as torotate freely and having an operation unit, wherein the first housing ismounted with one of the first optical and electric signals transmissionapparatus or the second optical and electric signals transmissionapparatus of the above-described optical and electric signalstransmission system of the present invention, the second housing ismounted with the other optical and electric signals transmissionapparatus of the optical and electric signals transmission system, andtransmission of optical and electric signals is performed between thefirst housing and the second housing by the optical and electric signalstransmission system.

According to this configuration, transmission of the optical andelectric signals is performed between the first housing having thedisplay unit and the second housing having the operation unit by theoptical and electric signals transmission system of the presentinvention which can be reduced in size and thickness. Thus, electronicequipment which is small, thin, and suitable for mounting on portableequipment is achievable.

In addition, little electromagnetic noise is generated by the firstoptical and electric signals transmission apparatus and the secondoptical and electric signals transmission apparatus, and theelectromagnetic noise of the whole of the electronic equipment can beextremely reduced. For this reason, it becomes unnecessary to shield anyof the optical and electric signals transmission apparatuses, and theelectronic equipment can be more space-saving and compact.

The electronic equipment may be, for example, a mobile phone, a PDA, anotebook PC, a portable DVD, digital music equipment, or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not intendedto limit the present invention, and wherein:

FIG. 1 is a perspective view showing a schematic configuration of areceptacle of an optical and electric signals transmission apparatusaccording to an embodiment of the present invention;

FIGS. 2( a) and 2(b) are perspective views of a plug to be fitted in arecess of a receptacle body in FIG. 1 seen from the front and the back;

FIG. 3 shows the configuration of the plug shown in FIGS. 2( a) and2(b);

FIG. 4 shows a method of inserting a plug body in and fixing it in arecess of a receptacle body;

FIG. 5 shows a method of mounting a photoelectric device to a receptaclebody;

FIG. 6 is a perspective view of a receptacle of an optical and electricsignals transmission apparatus according to an embodiment;

FIGS. 7( a) and 7(b) are perspective views of a plug to be fitted in arecess of a receptacle body in FIG. 6 seen from the front and the back;

FIGS. 8( a) and 8(b) are perspective views of a plug according to anembodiment seen from the front and the back;

FIG. 9 shows a connecting structure for connection between side faceelectrode terminals and copper wires in FIGS. 8( a) and 8(b);

FIG. 10 is a perspective view of a receptacle of an optical and electricsignals transmission apparatus according to an embodiment;

FIGS. 11( a) and (b) are perspective views of a plug to be fitted in arecess of a receptacle body in FIG. 10 seen from the back and the frontbottom;

FIG. 12 is a perspective view of a receptacle of an optical and electricsignals transmission apparatus according to an embodiment;

FIGS. 13( a) and 13(b) are perspective views of a plug to be fitted in arecess of a receptacle body in FIG. 12 seen from the back and the frontbottom;

FIG. 14 is a perspective view of a receptacle of an optical and electricsignals transmission apparatus according to an embodiment;

FIG. 15 is a perspective view of the receptacle shown in FIG. 14 seenfrom the opposite side;

FIGS. 16( a), 16(b), and 16(c) area front view, a side view, and abottom view showing the configuration of an optical transmitting andreceiving device in FIG. 14;

FIGS. 17( a), 17(b), and 17(c) area front view, a side view, and abottom view showing the configuration of a variation of an opticaltransmitting and receiving device shown in FIGS. 16( a), 16(b), and16(c);

FIG. 18 is a general view of an optical and electric signalstransmission apparatus in which the plug shown in FIGS. 7( a) and 7(b)and the optical transmitting and receiving device shown in FIGS. 16( a),16(b), and 16(c) are attached to a receptacle body;

FIG. 19 depicts a step in a procedure of assembling the optical andelectric signals transmission apparatus shown in FIG. 18;

FIGS. 20( a) and 20(b) depict a step in the assembling proceduresubsequent to that in FIG. 19;

FIG. 21 depicts a step in the assembling procedure subsequent to that inFIGS. 20( a) and 20(b);

FIGS. 22( a) and 22(b) depict a step in a procedure of mounting theoptical and electric signals transmission apparatus shown in FIG. 18 ona printed circuit board;

FIGS. 23( a) and 23(b) depict a step in the mounting proceduresubsequent to that in FIGS. 22( a) and 22(b);

FIGS. 24( a) and 24(b) are perspective views of a plug according to anembodiment seen from the back and the front bottom;

FIG. 25 is a perspective view of a receptacle of an optical and electricsignals transmission apparatus according to an embodiment;

FIGS. 26( a) and 26(b) are perspective views of a plug to be fitted in arecess of a receptacle body in FIG. 25 seen from the back and the frontbottom;

FIGS. 27( a) and 27(b) are perspective views of different receptacles ofan optical and electric signals transmission apparatus according to anembodiment;

FIGS. 28( a) and 28(b) are perspective views of a plug to be fitted in arecess of a receptacle body in FIGS. 27( a) and 27(b) seen from the backand the front bottom;

FIGS. 29( a) and 29(b) are perspective views of a plug according to anembodiment seen from the back and the front bottom;

FIG. 30 shows a procedure of forming the plug shown in FIGS. 2( a) and2(b);

FIG. 31 shows a procedure of forming the plug shown in FIGS. 8( a) and8(b);

FIG. 32 shows a procedure of forming the plug shown in FIGS. 2( a) and2(b) different from the procedure in FIG. 30;

FIG. 33 is a circuit diagram of an optical and electric signalstransmission system according to an embodiment using any one of theabove optical and electric signals transmission apparatuses;

FIG. 34 is a circuit diagram of an optical and electric signalstransmission system according to an embodiment;

FIG. 35 is a circuit diagram of an optical and electric signalstransmission system according to an embodiment;

FIG. 36 is a circuit diagram of an optical and electric signalstransmission system according to an embodiment;

FIG. 37 is a circuit diagram of an optical and electric signalstransmission system according to an embodiment;

FIG. 38 is a circuit diagram of an optical and electric signalstransmission system according to an embodiment;

FIG. 39 is a circuit diagram of an optical and electric signalstransmission system according to an embodiment;

FIGS. 40( a), 40(b), and 40(c) show electronic equipment using any oneof the above optical and electric signals transmission systems, in whichFIG. 40( a) is a front view showing an unfolded sate, FIG. 40 (b) showsa state of the equipment with the outer shell in FIG. 40 (a) removed,and FIG. 40( c) is a cross-sectional view taken along a directionperpendicular to an axis around which the equipment is folded;

FIG. 41 is a front view of a holder of a conventional plug and jack typeoptical and electric common use transmission device;

FIG. 42 is a side view of the conventional holder shown in FIG. 41;

FIG. 43 is a side view of an optical plug to be fitted in theconventional holder shown in FIGS. 41 and 42;

FIG. 44 is a cross-sectional view showing the state that the opticalplug shown in FIG. 43 is inserted in the conventional holder shown inFIGS. 41 and 42;

FIG. 45 is a cross-sectional view showing the state that an electricplug has been inserted in the conventional holder shown in FIGS. 41 and42;

FIG. 46 shows a male connecting component (plug) and a female connectingcomponent (jack) of a conventional connecting device;

FIG. 47 is a cross-sectional view of a plug of a conventional plug-jacktype connector; and

FIG. 48 shows how the conventional plug shown in FIG. 47 is fitted in ajack.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in detail below with referenceto embodiments shown in the figures.

First Embodiment

FIG. 1 is a perspective view showing a schematic configuration of areceptacle 51 of the optical and electric signals transmission apparatusof this embodiment. The receptacle body 52 is shaped like asubstantially rectangular parallelepiped provided with a rectangularrecess 53 and a rectangular hole 54 on a surface of the parallelepiped,and a photoelectric device 55 for optical signal transmission is to bereceived in the hole 54. The photoelectric device 55 includes alight-emitting element in the case that it is an optical signaltransmitting device, or includes a light-receiving element and alight-receiving signal processing circuit such as a trans-impedanceamplifier in the case that it is an optical receiving device. In eithercase, a lens 56 for optical coupling is provided. Mounting thephotoelectric device 55 to the receptacle body 52 is performed from thebottom of the receptacle body 52 as shown in FIG. 5. In FIG. 5, thereference numeral 57 denotes electrode terminals of the photoelectricdevice 55.

Furthermore, a plug is fitted in the recess 53 of the receptacle body52. Side face electrode terminals 58 for electric signal transmission,which are to be electrically connected to the electrode terminals of theplug, are provided from the inner wall of the recess 53 to the outerwall of the receptacle body 52. Furthermore, a rectangular notch 59 isprovided on a wall opposite to the hole 54-side wall of the recess 53,and side hooks 60 engaging with side hooks of the plug are provided onboth side walls defining the notch 59. In addition, two front hooks 61(only one of them is seen) engaging with front hooks of the plug areprovided on an inner wall facing the notch 59 of the recess 53.Furthermore, a notch 62 of a semicircular cross section is formed on apartition between the recess 53 and the hole 54, and the lens 56 of thephotoelectric device 55 faces the recess 53 through the notch 62.

FIGS. 2( a) and 2(b) are perspective views of a plug 63 to be fitted inthe recess 53 of the receptacle body 52. FIG. 2 (a) is a perspectiveview of the plug 63 seen from the front, and FIG. 2( b) is a perspectiveview of the plug 63 seen from the back. In FIGS. 2( a) and 2(b), theplug body 64 has an optical fiber cable 65 penetrating the plug bodyfrom the back side to the front side, and four copper wires 66 forelectric signal transmission. In FIGS. 2( a) and 2(b), the four copperwires are collectively numbered. As shown in FIG. 2( a), a cylindricaloptical fiber supporting unit 67 supporting the protruding optical fibercable 65, and two front hooks 68 (only one of them is seen) engagingwith the two front hooks 61 of the recess 53 of the receptacle body 52are provided on the front face of the plug body 64. The optical fibersupporting unit 67 is designed to fit in the notch 62 formed on thepartition to allow an end face of the optical fiber cable 65 to face thelens 56 when the plug 63 is fitted in the recess 53 of the receptaclebody 52.

As shown in FIG. 2( b), the plug body 64 has on its back a rectangularparallelepiped protrusion 69 having a width which is less than the widthof the plug body 64 and which allows the protrusion 69 to be fitted inthe notch 59 of the receptacle body 52. The optical fiber cable 65covered with a protective cover 70 and the four copper wires 66 held bya flexible substrate 71 protrude from an end face of the protrusion 69.Furthermore, side hooks 72 engaging with the side hooks 60 of the notch59 of the receptacle body 52 are provided on both sides of theprotrusion 69. Furthermore, a flexible substrate 71 holding the copperwires 66 extends from one side of the plug body 64 to the other side ofit through the bottom face of it. On each side of the flexible substrate71 lying on both sides of the plug body 64, as shown in FIGS. 2( a) and2(b), two side face electrode terminals 73 electrically connected to theside face electrode terminals 58 of the receptacle body 52 are provided.

The flexible substrate 71 is shaped like a letter “T” when it isdeveloped as shown in FIG. 3. Portions of the flexible substrate 71corresponding to both side protrusions in the shape of a letter “T” arebent so as to run along both sides of the plug body 64, the side faceelectrode terminals 73 are provided on both bent portions, and each ofthe side face electrode terminals 73 is mechanically and electricallyconnected with one of the four copper wires 66 inside the flexiblesubstrate 71. When the flexible substrate having the above configurationis mounted on the plug body 64, the relative position of the flexiblesubstrate 71 to the plug body 64 is decided by a positioning device (notshown) or the like and then the flexible substrate is mounted on theplug body 64 by adhesion with adhesive resin or press fitting.

The plug having the above configuration is fitted to the recess 53 ofthe receptacle body 52 as follows. In other words, as shown in FIG. 4,the plug body 64 is inserted in the recess 53 of the receptacle body 52in a direction (the direction of the arrow 75) perpendicular to theoptical axis (the direction of the arrow 74) of the photoelectric device55 which is fitted in the hole 54 of the receptacle body 52. The sidehooks 72 of the plug body 64 are engaged with the side hooks 60 of thereceptacle body 52, and the front hooks 68 of the plug body 64 areengaged with the front hooks 61 of the receptacle body 52, so that theplug is mounted in a predetermined location in the recess 53 of thereceptacle body 52.

In this state, an end face of the optical fiber cable 65 on the opticalfiber supporting unit 67 side of the plug 63 faces the lens 56 of thephotoelectric device 55, so that the optical fiber cable 65 is opticallycoupled to the photoelectric device 55. Furthermore, the side faceelectrode terminals 73 of the plug body 64 come into contact with theside face electrode terminals 58 of the receptacle body 52, so that thecopper wires 66 of the plug 63 are electrically connected to the sideface electrode terminals 58 of the receptacle 51.

As described above, in this embodiment, the recess 53 in which the plug63 is fitted and the hole 54 in which the photoelectric device 55 isfitted are provided side by side on a surface of the receptacle body 52,and the plug 63 is inserted in the recess 53 of the receptacle body 52in a direction perpendicular to the optical axis of the photoelectricdevice 55, so that the side hooks 72 and front hooks 68 of the plug body64 are engaged with the side hooks 60 and front hooks 61 of thereceptacle body 52, the optical fiber cable 65 of the plug body 64 isoptically coupled to the photoelectric device 55 of the receptacle body52, and the copper wires 66 of the plug body 64 are electricallyconnected to the side face electrode terminals 58 of the receptacle body52.

Thus, the plug 63 is allowed to be inserted in the recess 53 of thereceptacle body 52 in a direction perpendicular to the optical axis ofthe photoelectric device 55, so that it becomes unnecessary to keep aregion beyond the plug 63 for allowing insertion into and extractionfrom the receptacle body of the plug 63 along the optical axis. For thisreason, other components can be mounted in that region on a printedcircuit board (not shown) on which the receptacle 51 having thephotoelectric device 55 is to be mounted.

In other words, according to this embodiment, an optical and electricsignals transmission apparatus performing one-way optical communicationand one-way or two-way electrical communication at the same time isallowed to be reduced in size.

Furthermore, the receptacle body 52 of this embodiment is not requiredto cover the inserting side of the plug 63 in contrast to conventionaloptical and electric signals transmission apparatuses disclosed in thepatent documents which are structured in such a manner that a plug iscovered with a jack when the plug is inserted in the jack. Thus,according to this embodiment, the optical and electric signalstransmission apparatus performing one-way optical communication andone-way or two-way electrical communication at the same time can bereduced in thickness.

As described above, according to this embodiment, an optical andelectric signals transmission apparatus which is mountable on portableequipment being in the process of downsizing and which is able toperform both one-way optical communication and one-way or two-wayelectrical communication at the same time, is achievable.

In addition, in this embodiment, the side face electrode terminals 73 ofthe plug body 64 are formed on the flexible substrate 71, and are eachmechanically and electrically connected with any one of the four copperwires 66 inside the flexible substrate 71. Thus, it is not necessary toconnect the side face electrode terminals 73 to the copper wires 66inside the plug body 64, so that the structure of the plug body 64 canbe simplified and the plug body 64 can be reduced in size.

Second Embodiment

In the first embodiment, an optical and electric signals transmissionapparatus performing one-way optical communication has been described.However, in this embodiment, an optical and electric signalstransmission apparatus performing two-way optical communication will bedescribed. The same reference numerals are attached to the samecomponents as those in the first embodiment to omit detaileddescription.

FIG. 6 is a perspective view showing a schematic configuration of areceptacle 81 of the optical and electric signals transmission apparatusof this embodiment. A rectangular recess 53 and two rectangular holes 83and 84 are formed on a surface of a receptacle body 82, and the twoholes 83 and 84 are formed in a location corresponding to the locationof the hole 54 of the first embodiment. An optical signal transmittingdevice 85 including a light-emitting element is fitted in one 83 of thetwo holes 83 and 84. An optical signal receiving device 86 including alight-receiving element and a light-receiving signal processing circuitis fitted in the other hole 84. The devices 85 and 86 have lenses foroptical coupling 87 and 88, respectively.

Furthermore, a notch 89 of semicircular cross section is formed on apartition between the recess 53 and the hole 83, and the lens 87 of theoptical signal transmitting device 85 faces the recess 53 through thenotch 89. Likewise, a notch 90 of semicircular cross section is formedon the partition between the recess 53 and the hole 84, and the lens 88of the optical signal receiving device 86 faces the recess 53 throughthe notch 90. In addition, two front hooks 91 and 92 engaging with twofront hooks provided on a plug to be fitted in the recess 53 areprovided on an inner wall facing a notch 59 of the recess 53.

FIGS. 7( a) and 7(b) are perspective views of a plug 95 which is fittedin the recess 53 of the receptacle body 82. FIG. 7( a) is a perspectiveview of the plug 95 seen from the front, and FIG. 7 (b) is a perspectiveview of the plug 95 seen from the back. In FIGS. 7( a) and 7(b), theplug body 64 has two optical fiber cables 96 and 97 penetrating the plugbody from the back side to the front side, and four copper wires 66 forelectric signal transmission. As shown in FIG. 7( a), two cylindricaloptical fiber supporting units 98 and 99 supporting the protrudingoptical fiber cables 96 and 97, and two front hooks 100 and 101 engagingwith the two front hooks 91 and 92 of the recess 53 of the receptaclebody 82 are provided on the front of the plug body 64. The optical fibersupporting unit 98 and 99 are designed to fit in the notches 89 and 90formed on the partition to allow the end faces of the optical fibercable 96 and 97 to face the lenses 87 and 88 when the plug 95 is fittedin the recess 53 of the receptacle body 82.

As shown in FIG. 7( b), a rectangular parallelepiped protrusion 69having a width allowing it to be fitted in the notch 59 of thereceptacle body 82 is formed on the back of the plug body 64, andoptical fiber cables 96 and 97 having protective covers 102 and 103 andfour copper wires 66 held by a flexible substrate 71 protrude from theend face of the protrusion 69.

Other configuration and the method of fitting the plug 95 to thereceptacle 81 are same as those of the first embodiment.

Thus, according to this embodiment, the optical and electric signalstransmission apparatus performing two-way optical communication andone-way or two-way electrical communication at the same time can bereduced in size and thickness.

In other words, according to this embodiment, an optical and electricsignals transmission apparatus which can be mounted on portableequipment going to be reduced in size and thickness and is able toperform two-way optical communication and one-way or two-way electricalcommunication at the same time can be obtained.

In addition, the photoelectric device to be attached to the receptaclebody 82 is constituted by an optical signal transmitting device 85 andan optical signal receiving device 86 which are fabricated separately.Thus, the production yield of the whole of the photoelectric device isprevented from reducing, without being affected by that the productionyield of the light-emitting element or the light-receiving element islower than that of the other.

The optical fiber cables 96 and 97 may be single-core plastic fibercables or multi-core plastic fiber cables.

Third Embodiment

This embodiment relates to a connecting structure different from theconnecting structures for connection between the side face electrodeterminals 173 of the plug body 64 and the copper wires 66 in the firstand second embodiments. The same reference numerals are attached to thesame components as those in the first embodiment to omit detaileddescription.

FIGS. 8( a) and 8(b) are perspective views of a plug 105 in thisembodiment. FIG. 8( a) is a perspective view of the plug 105 seen fromthe front, and FIG. 8( b) is a perspective view of the plug 105 seenfrom the back. In FIGS. 8( a) and 8(b), the plug body 64 has an opticalfiber cable 65 penetrating the plug body from the back side to the frontside, and four copper wires 66 for electric signal transmission. Asshown in FIG. 8( a), the front configuration of the plug body 64 issimilar to that of the first embodiment.

As shown in FIG. 8( b), a protrusion 69 having a width allowing it to befitted in the notch 59 of the receptacle body 52 is formed on the backof the plug body 64, and the optical fiber cable 65 having a protectivecover 70 and a coaxial cable 106 having the four copper wires 66 coveredwith a protective cover protrude from the end face of the protrusion 69.Furthermore, two side face electrode terminals 107 to be electricallyconnected to the side face electrode terminals 58 of the receptacle body52 are provided on each of opposite lateral sides of the plug body 64.

FIG. 9 shows a connecting structure for connection between the side faceelectrode terminals 107 of the plug body 64 and the copper wires 66. Asshown in FIG. 9, the side face electrode terminals 107 are connectedwith the four copper wires 66 exposed from the protective cover of thecoaxial cable 106 by soldering. The side face electrode terminals 107are inserted in the direction of the arrow into grooves 108 provided onboth sides of the plug body 64, whereby side face electrode terminals107 are attached to both sides of the plug body 64. At that time, thefour copper wires 66 and part of the coaxial cables 106 are stored in,for example, storing grooves (not shown) or the like provided on thebottom of the plug body 64. Other configuration and the method offitting the plug 105 to the receptacle 51 are same as those of the firstembodiment.

As described above, in this embodiment, the four copper wires 66 exposedfrom the protective cover of the coaxial cable 106 are connected to theside face electrode terminals of the plug body 64 by soldering. Thus,the electric signal transmission line which is not limited in bendingdirection can be obtained.

FIGS. 8( a) and 8(b) depict the plug 105 for one-way opticalcommunication as an example, although in the case that the plug is fortwo-way optical communication like one as shown in FIGS. 7( a) and 7(b)in the second embodiment as well, copper wires of the coaxial cable canbe similarly connected to side face electrode terminals of the plugbody.

Furthermore, the copper wires 66 may be coaxial small-gauge wires asnecessary.

Fourth Embodiment

This embodiment relates to a connecting structure, different from theconnecting structures in the first to third embodiments, for connectionbetween receptacle side face electrode terminals and a plug sideelectric transmission line. The same reference numerals are attached tothe same components as those in the first embodiment to omit detaileddescription.

FIG. 10 is a perspective view showing a schematic configuration of areceptacle 111 of the optical and electric signals transmissionapparatus of this embodiment. A rectangular recess 53 and a rectangularhole 54 are formed on a surface of a receptacle body 112, and aphotoelectric optical signal transmitting device 55 is fitted in thehole 54. Furthermore, front hooks 61 for engaging with front hooksprovided on a plug to be fitted in the recess 53 are provided on theinner wall facing the notch 59 of the recess 53.

Furthermore, bottom face electrode terminals for electric signaltransmission 113 electrically connected to electrode terminals of theplug are provided from the bottom face of the recess 53 of thereceptacle body 112 to the outer wall of the receptacle body 112 throughthe inner wall of the recess 53. Provided on portions 113 a formed onthe bottom face of the recess 53 of the bottom face electrode terminals113 are circular contacts 114 having a predetermined thickness to secureeffective contact with the electrode terminals of the plug.

FIGS. 11( a) and 11(b) are perspective views of a plug 115 to be fittedin the recess 53 of the receptacle body 112. FIG. 11( a) is aperspective view of the plug 115 seen from the back, and FIG. 11( b) isa perspective view of the plug 115 seen from the front bottom. In FIGS.11( a) and 11(b), the plug body 64 has an optical fiber cable 65penetrating the plug body from the back side to the front side, and twocopper patterns for electric signal transmission 116. As shown in FIG.11( b), the front configuration of the plug body 64 is similar to thatof the first embodiment.

Furthermore, as shown in FIG. 11( a), a protrusion 69 having a widthallowing it to be fitted in the notch 59 of the receptacle body 112 isformed on the back of the plug body 64. In addition, the two copperpatterns 116 held by a flexible substrate 117 protrude from the bottomof the plug body 64 in the same direction as the optical fiber cable 65.As shown in FIG. 11( b), an end portion of the flexible substrate 117 isattached to the bottom face of the plug body 64 by adhesion or the like.Two bottom face electrode terminals 118 to be electrically connected tothe bottom face electrode terminals 113 of the receptacle body 112 areprovided on the bottom face of the plug body 64 in locationscorresponding to the contacts 114 of the receptacle body 112. The twobottom face electrode terminals 118 are mechanically and electricallyconnected with the two copper patterns 16 inside the flexible substrate117.

Other configuration and the method of fitting the plug 115 to thereceptacle 111 are same as those of the first embodiment.

As described above, in this embodiment, the two copper patterns 116 areheld by the flexible substrate 117 to make the electrical transmissionline for electrical communication. Furthermore, an end portion of theflexible substrate 117 is mounted on the bottom face of the plug body64, and the bottom face electrode terminals 118 are provided on theflexible substrate for electrical connection to the bottom faceelectrode terminals 113 of the receptacle body 112. In addition, thebottom face electrode terminals 113 are provided from the bottom face ofthe recess 53 of the receptacle body 112 to the outer wall of thereceptacle body 112 through the inner wall of the recess 53, and thecontacts 114 capable of effective contact with the bottom face electrodeterminals of the plug 115 are provided on portions 113 a formed on thebottom face of the recess 53 of the bottom face electrode terminals 113.

Furthermore, the plug 115 is inserted in the recess 53 of the receptaclebody 112 in a direction perpendicular to the optical axis of thephotoelectric device 55, so that the optical fiber cable 65 of the plugbody 64 is optically coupled to the photoelectric device 55 of thereceptacle body 112, and the copper patterns 116 of the plug body 64 areelectrically connected to the side face electrode terminals 113 of thereceptacle body 112.

Thus, the electrode terminal structure of the plug body 64 is simplifiedand the plug body 64 is reduced in size.

Fifth Embodiment

This embodiment relates to an electrode terminal structure differentfrom electrode terminal structures of plug bodies 64 in the first tofourth embodiments. The same reference numerals are attached to the samecomponents as those in the first embodiment to omit detaileddescription.

FIG. 12 is a perspective view showing a schematic configuration of areceptacle 121 of the optical and electric signals transmissionapparatus of this embodiment. Side face electrode terminals for electricsignal transmission 58 to be electrically connected to electrodeterminals of a plug as inserted are provided from the inner wall of therecess 53 of the receptacle body 112 to the outer wall of the receptaclebody 112. In addition, bottom face electrode terminals for electricsignal transmission 123 to be electrically connected to electrodeterminals of a plug as inserted are provided from the bottom face of therecess 53 to the outer wall of the receptacle body 112 through the innerwall of the recess 53. Contacts 124 are provided on portions 123 a onthe bottom face of the recess 53 of the bottom face electrode terminals123.

FIGS. 13( a) and 13(b) are perspective views of a plug 125 to be fittedin the recess 53 of the receptacle body 122. FIG. 13 (a) is aperspective view of the plug 125 seen from the back, and FIG. 13 (b) isa perspective view of the plug 125 seen from the front bottom. In FIGS.13( a) and 13(b), like the first embodiment, a flexible substrate 71holding four copper wires 66 is disposed from one side face of the plugbody 64 to the other side face across the bottom face of the flexiblesubstrate 71. Each side of the flexible substrate 71 lying on both sidesof the plug body 64, as shown in FIGS. 13( a) and 13(b) is provided withtwo side face electrode terminals 73 electrically connected to the sideface electrode terminals 58 of the receptacle body 122.

In addition, as shown in FIG. 13( b), an end portion of the flexiblesubstrate 126 holding the two copper patterns 127 is laid on and fixedto the upper side (outside) of the flexible substrate 71 on the bottomface of the plug body 64. Two bottom face electrode terminals 128electrically connected to the bottom face electrode terminals 123 of thereceptacle body 122 are provided on the flexible substrate 126 inlocations corresponding to the contacts 124 of the receptacle body 122.

Other configuration and the method of fitting the plug 125 to thereceptacle 121 are same as those of the first embodiment.

As described above, the electrode terminal connecting structure of thisembodiment is achieved by a connecting structure for connection betweenthe side face electrode terminals 58 of the receptacle body 122 and theside face electrode terminals 73 of the plug 64 similar to that of thefirst embodiment in combination with a connecting structure forconnection between the bottom face electrode terminals 123 of thereceptacle body 122 and the bottom face electrode terminals 128 of theplug body 64 similar to that of the fourth embodiment.

According to this embodiment, the two copper patterns 127 held by theflexible substrate 126 may be assigned to a power supply and a groundwhich need relatively thick electrical transmission lines, and the fourcopper wires 66 held by the flexible substrate 71 may be assigned toother electric signals.

Thus, the plug 125 is allowed to be made small and have an increasednumber of electrical transmission lines.

Sixth Embodiment

This embodiment relates to a photoelectric device different from thephotoelectric devices of the first to fifth embodiments. The samereference numerals are attached to the same components as those in thefirst embodiment to omit detailed description.

FIGS. 14 and 15 are perspective views showing a schematic configurationof a receptacle 131 of the optical and electric signals transmissionapparatus of this embodiment. FIGS. 14 and 15 are perspective views ofthe receptacle 131 seen from sides opposite to each other. A rectangularrecess 133 and a rectangular hole 134 are formed on a surface of thereceptacle body 132, and an optical transmitting and receiving device135 is fitted in the hole 134. The optical transmitting and receivingdevice 135 has an optical signal transmitting device section including alight-emitting element, and an optical signal receiving device sectionincluding a light-receiving element and a light-receiving signalprocessing circuit. The optical signal transmitting device section has alens 136 for optical coupling, and the optical signal receiving devicesection has a lens 137 for optical coupling. A groove 138 is provided ona boundary portion between the device sections so that the opticalsignal transmitting device section and the optical signal receivingdevice section of the optical transmitting and receiving device 135 donot affect each other. On the other hand, a rib 139 which protrudes tothe optical transmitting and receiving device 135 and engages with thegroove 138 of the optical transmitting and receiving device 135 isprovided on a partition between the recess 133 and the hole 134 of thereceptacle body 132.

FIG. 15 is a perspective view of the receptacle 131 seen from theoptical transmitting and receiving device 135 to be fitted in the hole134 of the receptacle 131. In FIG. 15, the reference numeral 140 denoteslead terminals for the optical transmitting and receiving device 135,which are used as surface mounting terminals.

FIGS. 16( a), 16(b), and 16(c) show the optical transmitting andreceiving device 135 to be fitted in the hole 134 of the receptacle body132. FIG. 16( a) is a front view of the device 135, FIG. 16( b) is aside view of the device 135, and FIG. 16( c) is a bottom view of thedevice 135. In the optical transmitting and receiving device 135, alight-emitting element 142 for optical signal transmission, alight-receiving element 143 for optical signal reception and alight-receiving signal processing circuit (IC) 144 are mounted on a leadframe 141 connected with the lead terminals 140 by bonding withconductive resin such as silver paste. Electrodes of the light-emittingelement 142, light-receiving element 143, and light-receiving signalprocessing circuit 144 are electrically connected with correspondinglead terminals 140 by wire bonding with gold wires 145 or the like.

The light-emitting element 142, light-receiving element 143, andlight-receiving signal processing circuit 144 mounted on the lead frame141 are sealed with transparent resin 142. Furthermore, in order toincrease the light extraction efficiency, a lens 136 for light emissionmade of transparent resin 146 is disposed just above the light-emittingelement 142. Furthermore, in order to increase the light-receptionefficiency, a lens 137 for light reception similarly made of thetransparent resin 146 is disposed just above the light-receiving element143. On the boundary portion between an optical signal transmittingdevice section 147 and an optical signal receiving device section 148, agroove 138 bottomed at the lead frame 141 to separate the light-emittingelement 142 from the light-receiving element 143 is provided so that thelight-emitting element 142 and the light-receiving element 143 do notaffect each other. In addition, the lead terminals 140 are bent 90degrees at positions just outside the sealing transparent resin 146 tobe surface mounting terminals. Furthermore, a protrusion 149 provided onthe light-outgoing side of the optical signal transmitting devicesection 147 and a protrusion 150 provided on the light-incoming side ofthe optical signal receiving device section 148 serve as positioningstoppers when the optical transmitting and receiving device 135 ismounted in the receptacle 131.

Furthermore, other configuration including the plug is same as that ofthe second embodiment performing two-way optical communication. Themethod of fitting the plug to the receptacle 131 in this case is alsosame as that of the second embodiment.

As described above, in this embodiment, the optical transmitting andreceiving device 135, which has the optical signal transmitting devicesection 147 and the optical signal receiving device section 148 and isformed with the groove 138 separating the light-emitting element 142from the light-receiving element 143 between the optical signaltransmitting device section 147 and the optical signal receiving devicesection 148, is fitted in the hole 134 of the receptacle body 132. Thus,in contrast to the case that the optical signal transmitting devicesection 147 and the optical signal receiving device section 148 areformed as separate components, mounting of the photoelectric device tothe hole 134 of the receptacle body 132 may be simple, therebyincreasing the manufacturing efficiency.

Furthermore, the light-emitting element 142 of the optical signaltransmitting device section 147, and the light-receiving element 143 andlight-receiving signal processing circuit 144 of the optical signalreceiving device section 148 are mounted on the lead frame 141 andsealed with the transparent resin 146. Thus, a small and space-savingreceptacle 131 of a lead type can be obtained.

FIGS. 17( a), 17(b), and 17(c) show a variation of the opticaltransmitting and receiving device 135. The same reference numerals areattached to the same components as those of the optical transmitting andreceiving device 135 in FIGS. 16( a), 16(b), and 16(c). In the opticaltransmitting and receiving device 135, the light-emitting element 142 ofthe optical signal transmitting device section 147, and thelight-receiving element 147 and light-receiving signal processingcircuit 144 of the optical signal receiving device section 148 arebonded to a rigid printed circuit board 151 with conductive resin suchas silver paste. Furthermore, the electrodes of the light-emittingelement 142, light-receiving element 143, and light-receiving signalprocessing circuit 144 are electrically connected with correspondingcircuit patterns (not shown) by wire bonding with gold wires 145 or thelike.

The light-emitting element 142 of the optical signal transmitting devicesection 147 mounted on the rigid printed circuit board 151 is sealedwith transparent resin 152. Likewise, the light-receiving element 143and the light-receiving signal processing circuit 144 of the opticalsignal receiving device section 148 mounted on the rigid printed circuitboard 151 are sealed with transparent resin 153. On the boundary portionbetween the optical signal transmitting device section 147 and theoptical signal receiving device section 148, a groove 138 bottomed atthe rigid printed circuit board 151 to separate the light-emittingelement 142 from the light-receiving element 143 is provided so that thelight-emitting element 142 and the light-receiving element 143 do notaffect each other. Furthermore, in order to increase the lightextraction efficiency, the lens 136 for light emission made oftransparent resin 152 is disposed just above the light-emitting element142. Furthermore, in order to increase the light-reception efficiency,the lens 137 for light reception similarly made of transparent resin 153is disposed just above the light-receiving element 143. The element sidecircuit patterns are mechanically and electrically connected viathrough-holes 154 to output terminals 155 which serve as surfacemounting terminals. Furthermore, a protrusion 149 provided on thelight-outgoing side of the optical signal transmitting device section147 and a protrusion 150 provided on the light-incoming side of theoptical signal receiving device section 148 serve as positioningstoppers used when the optical transmitting and receiving device 135 isattached to the receptacle 131.

First Example

FIGS. 18 to 21 show a concrete example of an optical and electricsignals transmission apparatus in which the electrode terminalconfiguration of the fifth embodiment is applied to the generalstructure of the sixth embodiment. In the sixth embodiment, theconfiguration of the plug is not specifically described, but the plugperforming two-way optical communication of the second embodiment may beused. Thus, in this example, description will be made using the plug 95of the second embodiment. For easy understanding of the description, thesame reference numerals as those of the sixth embodiment are attached tothe components of the receptacle and the optical transmitting andreceiving device, the same reference numerals as those of the fifthembodiment are attached to the electrode terminals, and the samereference numerals as those of the second embodiment are attached to thecomponents of the plug.

In this example, the heights of the receptacle 131 and the plug 95 aremade as small as possible like about 1 mm or less. FIG. 18 shows thestate that the optical transmitting and receiving device 135 and theplug 95 are placed in the receptacle 131. The optical transmitting andreceiving device 135 of this example has a width larger than theeffectual width of the receptacle body 132. Furthermore, side faceelectrode terminals 58 are each provided from an inner wall of therecess of the receptacle body 132 to an outer wall of the receptaclebody 132. In addition, bottom face electrode terminals 123 are providedfrom the bottom face of the recess to the outer wall of the receptaclebody 132 across the inner wall of the recess. The plug 95 is fitted inthe recess of the receptacle body 132, and thus the side face electrodeterminals of the plug 95 are connected with the side face electrodeterminals 58 of the receptacle body 132, while the bottom face electrodeterminals of the plug 95 are connected with the bottom face electrodeterminals of the receptacle body 132.

The optical and electric signals transmission apparatus shown in FIG. 18is assembled as follows. First, as shown in FIG. 19, the opticaltransmitting and receiving device 135 having an optical signaltransmitting device section 147 and an optical signal receiving devicesection 148 are inserted from below in the hole 134 of the receptaclebody 132 and fixed thereto. In this sate, the lens for light emission136 of the optical signal transmitting device section 147 and the lensfor light reception 137 of the optical signal receiving device section148 face the recess 133 of the receptacle body 132. Next, the bottomface electrode terminals 123 and the side face electrode terminals 58are put from above and fixed to the walls of the recess 133 of thereceptacle body 132. The side face electrode terminals 58 are shaped tohave a spring characteristic. Furthermore, in this example, up to 12side face electrode terminals 58 can be mounted.

Next, assembly of the plug 95 will be described according to FIGS. 20(a) and 20(b). As shown in FIG. 20( a), a pair of optical fiber cables 96and 97 for transmission and reception having a diameter of 500 μm orless are inserted in and fixed to the plug body 64. In addition, acombination of a flexible substrate 71 having side face electrodeterminals 73 and a flexible substrate 126 having bottom face electrodeterminals 128 (see FIG. 20( b)) stacked on the flexible substrate 71 isfixed to the bottom face and side faces of the plug body 64. Theflexible substrate 71 having side face electrode terminals 73 and theflexible substrate 126 having bottom face electrode terminals 128 aredifferent flexible substrates and each constitutes an electrical signaltransmission line. In this example, the two bottom face electrodeterminals 128 are assigned to a power supply and a ground, while theside face electrode terminals 73 are assigned to electric signals.Furthermore, in this example, the flexible substrate 71 is laid underthe flexible substrate 126, but the flexible substrate 126 may be laidunder the flexible substrate 71 koko

Next, the plug 95 assembled as shown in FIG. 20( a) is inserted in therecess 133 of the receptacle 131 assembled as shown in FIG. 19 fromabove as shown in FIG. 21 and is attached to the receptacle 131 as shownin FIG. 18. At that time, the end faces of the optical fiber cables 96and 97 of the plug 95 are positioned to face the lens for light emission136 and the lens for light reception 137 of the optical transmitting andreceiving device 135.

The optical and electric signals transmission apparatus assembled likethis is mounted on a printed circuit board as shown in FIGS. 22( a),22(b), 23(a) and 23(b). In other words, as shown in FIGS. 22( a) and22(b), a surface around a region 161 facing the recess 133 of the bottomface of the receptacle 131 is made lower than the region 161 by apredetermined height as a mounting surface for the printed circuit board162. The region 161 will be referred to as a protrusion hereafter.Furthermore, a mounting hole 163 having a shape allowing the protrusion161 of the receptacle 131 to be fitted in the hole is formed in theprinted circuit board 162. As shown in FIGS. 23( a) and 23(b), theprotrusion 161 of the receptacle 131 is fitted in the mounting hole 163of the printed circuit board 162, and the mounting surface of thereceptacle 131 is brought into contact with the surface of the printedcircuit board 162 and fixed to it, so that the optical and electricsignals transmission apparatus of this example is mounted on the printedcircuit board 162.

As described above, when the optical and electric signals transmissionapparatus is mounted on the printed circuit board 162, the protrusion162 of the bottom face of the receptacle 131 is fitted in the mountinghole 163 of the printed circuit board 162. Thus, amounting location forthe receptacle 131 is fixed, and the height above the printed circuitboard 162 of the receptacle 131 can be reduced by the protrusion heightof the protrusion 161, so that the thickness of an apparatus constitutedby the optical and electric signals transmission apparatus and theprinted circuit board can be reduced.

Seventh Embodiment

This embodiment relates to an electric signal transmission linestructure different from the electric signal transmission line structureof the plug body 64 of fifth embodiment. The same reference numerals areattached to the same components as those in the fifth embodiment to omitdetailed description.

In the fifth embodiment, two different flexible substrates, which are aflexible substrate 71 which holds four copper wires 66 and has four sideface electrode terminals 73 and a flexible substrate 126 which holds twocopper patterns 127 and has two bottom face electrode terminals 128, arestacked and fixed to the bottom face of the plug body 64.

In contrast to this, as shown in FIGS. 24( a) and 24(b), in the plug 171of this embodiment, the electric signal transmission line of thisembodiment is constituted by a flexible substrate 175 which holds sixcopper wires 172 and has two side face electrode terminals 173 on eachside of it, that is, four side face electrode terminals 173 in total,and two bottom face electrode terminals 174 in locations of the bottomface of the plug body 64.

Other configuration and the method of fitting the plug 171 to thereceptacle are same as those of the fifth embodiment.

As described above, in this embodiment, the side face electrodeterminals 173 and the bottom face electrode terminals 174 are formed onthe common flexible substrate 175. Thus, the plug 171 for optical andelectric signals transmission which has many electrode terminals and issmall and thin can be realized.

Eighth Embodiment

This embodiment relates to an optical and electric signals transmissionline structure different from the optical and electric signalstransmission line structures of the plug bodies 64 of first to seventhembodiments. The same reference numerals are attached to the samecomponents as those in the first to fourth embodiments to omit detaileddescription.

FIG. 25 is a perspective view showing a schematic configuration of thereceptacle 181 of the optical and electric signals transmissionapparatus of this embodiment. A rectangular recess 183 and a rectangularhole 184 continuing to it are formed on a surface of the receptacle body182, and a photoelectric device for optical signal transmission 55 isfitted in the hole 184. Furthermore, a plug described later is fitted inthe recess 183. Two front hooks 61 (only one of them is seen) engagingwith front hooks provided on the plug are provided on the partitionbetween the recess 183 and the hole 184.

Furthermore, bottom face electrode terminals for electric signaltransmission 113 electrically connected to electrode terminals of theloaded plug are provided from the bottom face of the recess 183 of thereceptacle body 182 to the outer wall of the receptacle body 182 via theinner wall of the recess 183. Provided on portions 113 a formed on thebottom face of the recess 53 of the bottom face electrode terminals 113are circular contacts 114 having a predetermined thickness so that thebottom face electrode terminals are able to effectively come intocontact with the electrode terminals of the plug.

FIGS. 26( a) and 26(b) are perspective views of a plug 186 which isfitted in the recess 183 of the receptacle body 182. FIG. 26( a) is aperspective view of the plug 186 seen from the back, and FIG. 26( b) isa perspective view of the plug 186 seen from the front bottom. In FIGS.26( a) and 26(b), an end portion of a laminate consisting of an opticalwaveguide holder 189 shaped like a flat plate holding an opticalwaveguide 188 and a flexible substrate 117 holding two copper patterns116 for electric signal transmission is mounted on the bottom face ofthe plug body 187 by, for example, adhesion or the like.

Two bottom face electrode terminals 118 electrically connected to thebottom face electrode terminals 113 of the receptacle body 182 areprovided in locations corresponding to the contacts 114 of thereceptacle body 182 of the flexible substrate 117. The two bottom faceelectrode terminals 118 are mechanically and electrically connected withthe two copper patterns 116 inside the flexible substrate 117.

In contrast to this, the optical waveguide holder 189 extends to an endof the plug body 187 and is located in such a manner that an end face ofthe optical waveguide 188 faces the lens 56 of the photoelectric device55 when the plug 186 is fitted in the recess 183 of the receptacle body182. Furthermore, two front hooks 68 engaging with two front hooks 61provided on the partition 185 of the receptacle body 182 are provided onthe front face of the plug body 187.

Other configuration and the method of fitting the plug 186 to thereceptacle 181 are same as those of the first and fourth embodiments.

As described above, in this embodiment, the optical signal transmissionline is constituted by the optical waveguide holder 189 shaped like aflat plate holding the optical waveguide 188, and is laid on theflexible substrate 117 holding the two copper patterns 116 which areelectrical signal transmission lines. In this way, the optical signaltransmission line and the electric signal transmission lines are madethin, so that the thickness of the optical and electric signalstransmission line can be reduced, and furthermore the thickness of theplug 186 can also be reduced.

In this embodiment, the bottom face electrode terminals 113 providedfrom the bottom face of the recess 183 of the receptacle body 182 to theouter wall of the receptacle body 182 via the inner wall of the recess183 are used as electrode terminals for the electric signal transmissionlines, but it may be perfectly all right to use side face electrodeterminals provided from the inner wall of the recess 183 to the outerwall of the receptacle body 182 as electrode terminals for the electricsignal transmission lines. However, in this case, it is necessary toform side face electrode terminals also on the plug 186.

Ninth Embodiment

In contrast to the eighth embodiment that relates to a one-way opticalsignal transmission line, this ninth embodiment relates to a two-wayoptical signal transmission line. The same reference numerals areattached to the same components as those in the eighth and secondembodiments to omit detailed description.

FIGS. 27( a) and 27(b) are perspective views each showing a schematicconfiguration of a receptacle of the optical and electric signalstransmission apparatus of this embodiment. FIG. 27( a) shows areceptacle 191 to which an optical transmitting and receiving device ismounted. In contrast to this, FIG. 27( b) shows a receptacle 195 towhich an optical signal transmitting device and an optical signalreceiving device are individually mounted as in the second embodiment.

In FIG. 27( a), a rectangular recess 183 and a rectangular hole 184continuing from the recess 183 are formed on a surface of a receptaclebody 182, and an optical transmitting and receiving device 192constituted by an optical signal transmitting device section and anoptical signal receiving device section which are formed in one piece isfitted in the hole 184. In addition, a plug described later is fitted inthe recess 183. The optical transmitting and receiving device 192 has alens 193 for optical transmission and a lens 194 for optical reception.

In FIG. 27( b), a rectangular recess 183 and two rectangular holes 197and 198 continuing from the recess 183 are formed on a face of areceptacle body 196, and the two holes 197 and 198 are formed inlocations corresponding to the location of the hole 184 of thereceptacle body 182 shown in FIG. 27( a). An optical signal transmittingdevice 85 including a light-emitting element is fitted in one 197 of thetwo holes 197 and 198. Furthermore, an optical signal receiving device86 including a light-receiving element and a light-receiving signalprocessing circuit is fitted in the other hole 198. The devices 85 and86 have lenses 87 and 88 for optical coupling, respectively. Inaddition, a plug described later is fitted in the recess 183.

FIGS. 28( a) and 28(b) are perspective views of a plug 199 to be fittedin the recess 183 of the receptacle body 182 in FIG. 27( a) or thereceptacle body 196 in FIG. 27( b). FIG. 28 (a) is a perspective view ofthe plug seen from the back, and FIG. 28 (b) is a perspective view ofthe plug seen from the front bottom. In FIGS. 28( a) and 28(b), an endportion of a laminate consisting of an optical waveguide holder 202shaped like a flat plate holding an optical waveguide 200 for opticalsignal transmission and an optical waveguide 201 for optical signalreception, and a flexible substrate 117 for electric signal transmissionhaving a configuration similar to that of the eighth embodiment ismounted on the bottom face of the plug body 187 by, for example,adhesion or the like.

The optical waveguide holder 202 extends to an end of the plug body 187and is located in such a manner that an end face of the opticalwaveguide 200 (201) faces the lens 193 (194) of the optical transmittingand receiving device 192 when the plug 199 is fitted in the recess 183of the receptacle body 182, or in such a manner that an end face of theoptical waveguide 200 (201) faces the lens 87 of the optical signaltransmitting device 85 (the lens 88 of the optical signal receivingdevice 86).

Other configuration and the method of fitting the plug 199 to thereceptacle 191 or 195 are same as those of the eighth embodiment.

As described above, in this embodiment, the optical signal transmissionline is constituted by the optical waveguide holder 202 shaped like aflat plate holding the optical waveguide for optical signal transmission200 and the optical waveguide for optical signal reception 201. Thus,the thickness of the plug 199 capable of performing two-way opticalcommunication and one-way or two-way electrical communication at thesame time can be reduced.

In this embodiment, the bottom face electrode terminals 113 providedfrom the bottom face of the recess 183 of the receptacle body 182, 196to the outer wall of the receptacle body 182, 196 via the inner wall ofthe recess 183 are used as electrode terminals for the electric signaltransmission line, but it may be perfectly all right to use side faceelectrode terminals provided from the inner wall of the recess 183 tothe outer wall of the receptacle body 182, 196 as electrode terminalsfor the electric signal transmission line.

Tenth Embodiment

In the above-described eighth and ninth embodiments, an optical andelectric signals transmission line is constituted by a laminateconsisting of an optical waveguide holder holding an optical waveguideand a flexible substrate holding a copper pattern. However, in thisembodiment, an optical and electric signals transmission line isconstituted by a single-layer component. The same reference numerals areattached to the same components as those in the ninth embodiment to omitdetailed description.

FIGS. 29( a) and 29(b) are perspective views of a plug 211 in thisembodiment. FIG. 29( a) is a perspective view of the plug seen from theback, and FIG. 29( b) is a perspective view of the plug seen from thefront bottom. The plug 211 is attached to the receptacle body 182 shownin FIG. 27 (a) of the ninth embodiment or a receptacle body 196 shown inFIG. 27( b) of the ninth embodiment.

In FIGS. 29( a) and 29(b), an end portion of a flexible substrate 215holding an optical waveguide for optical signal transmission 212, anoptical waveguide for optical signal reception 213, and two copperpatterns for electric signal transmission 214 is mounted on the bottomface of the plug body 187 by, for example, adhesion or the like. In thisembodiment, the optical waveguides 212 and 213 are disposed inside theplug more than the copper patterns 214, but the copper patterns 214 maybe disposed inside the plug more than the optical waveguides.Furthermore, the flexible substrate 215 is obtained by forming theoptical waveguides 212 and 213 first when the resin portion is made ofpolyimide resin and then forming the copper patterns 214.

Furthermore, two bottom face electrode terminals 216 electricallyconnected to the bottom face electrode terminals 113 of the receptaclebody 182, 196 are provided in locations corresponding to the contacts114 of the bottom face electrode terminals 113 of the receptacle body182, 196 of the ninth embodiment of the flexible substrate 215 mountedon the bottom face of the plug body 187. The two bottom face electrodeterminals 216 are mechanically and electrically connected with the twocopper patterns 214 inside the flexible substrate 215.

In addition, the flexible substrate 215 extends to an end of the plugbody 187 and is located in such a manner that end faces of the opticalwaveguide 212, 213 face the lenses 193, 194 of the optical transmittingand receiving device 192 when the plug 211 is fitted in the recess 183of the receptacle body 182 of the ninth embodiment, or in such a mannerthat end faces of the optical waveguides 212, 213 face the lens 87 ofthe optical signal transmitting device 85 and the lens 88 of the opticalsignal receiving device 86 when the plug 211 is fitted in the recess 183of the receptacle body 196 of the ninth embodiment.

Other configuration and the method of fitting the plug 211 to thereceptacle are same as those of the ninth embodiment.

As described above, in this embodiment, the optical and electric signalstransmission line is constituted by a single layer component of theflexible substrate 215 holding the optical waveguides 212 and 213 foroptical signal transmission and the copper patterns for electric signaltransmission 214. Thus, the thickness of the plug 211 can be furtherreduced as compared with the case that the optical and electric signalstransmission line is constituted by the laminated component of theoptical waveguide holder holding the optical waveguides and the flexiblesubstrate holding the copper patterns as in the case of the eighthembodiment or the ninth embodiment.

In this embodiment, the case that two-way optical communication isperformed is described as an example. However, it is needless to saythat this embodiment may be applied to the case that one-way opticalcommunication is performed.

Eleventh Embodiment

This embodiment relates to a method of forming the plug 63 of the firstembodiment. FIG. 30 shows a procedure for forming the plug 63. The samereference numerals are attached to the same components as those in thefirst embodiment to omit detailed description.

First, a flexible substrate 71 is formed which holds four copper wires66 and has side face electrode terminals 73 on both sides of it. Next,as shown in FIG. 30, a plug body 64 which has an optical fibersupporting unit 67 with a through-hole 221 for penetration of an opticalfiber cable 65 on one end of the plug body and a protrusion 69 on theother end of the plug body, and is equipped with the flexible substrate71 provided from one side to the other side through the bottom face isinsert-molded of resin. As described above, in this embodiment, theflexible substrate 71 is integrated with the plug body 64 by insertmolding, so that the flexible substrate 71 and the side face electrodeterminals 73 are accommodated in the plug body 64. Thus, the width ofthe plug 63 can be reduced as compared with the case that the flexiblesubstrate 71 is directly stuck to both sides of the plug body 64 asshown in FIG. 2 in the first embodiment.

After that, an optical fiber cable 65 is inserted into the through-hole221 of the plug body 64 to which the flexible substrate 71 is attachedcompleting the plug 63.

As described above, in this embodiment, the plug 63 is made by attachingand fixing the flexible substrate 71 having the copper wires 66 and theside face electrode terminals 173 formed by insert-molding to the plugbody 64 molded of resin and inserting the optical fiber cable 65 intothe through-hole 221. Thus, the process of assembling the plug 63 can besimplified to increase the productivity.

In this embodiment, the plug 63 for one-way optical communication isdescribed as an example, but this embodiment may be applied to a plugfor two-way optical communication having two optical fiber cables.Furthermore, even if the electrode terminals are bottom face electrodeterminals like those of the fourth embodiment, the flexible substrate 71can be formed by insert-molding.

Twelfth Embodiment

This embodiment relates to a method of forming the plug 105 of the thirdembodiment. FIG. 31 shows a procedure for forming the plug 105. The samereference numerals are attached to the same components as those in thethird embodiment to omit detailed description.

First, a component is formed in which four metal electrodes becoming theside face electrode terminals 107 are connected with a supporting bar231 through connecting branches 233 having soldering portions. Byinsert-molding for the metal electrodes, the soldering portions 232, andthe connecting branches 233, a plug body 64 is formed which has sideface electrode terminals 107 on both sides of it, and an optical fibersupporting unit 67 equipped with a through-hole 234 for penetration ofan optical fiber cable 65 at one end of the plug body, and a protrusion69 at the other end of the plug body.

After that, the supporting bar 231 attached to the plug body 64 is cutoff at the boundaries of the connecting branches 233. After that, thetips of four copper wires 66 of a coaxial cable 106 having a protectivecover for protection of the copper wires 66 are soldered to thesoldering portions 232 of the plug body 64.

After that, an optical fiber cable 65 is inserted into the through-hole234 of the plug body 64 to which the coaxial cable 106 has been attachedcompleting the plug 105.

As described above, in this embodiment, the plug 105 is made bysoldering the copper wires 66 of the coaxial cable 106 to the plug body64 having the side face electrode terminals 107 formed by insert-moldingand inserting the optical fiber cable 65 into the through-hole 234.Thus, the plug 105 having an electric signal transmission line which isexcellent in flexibility can be formed easily.

In FIG. 31, the plug for one-way optical communication 105 is depictedas an example. However, also in the case of a plug for two-way opticalcommunication like that of the second embodiment, a plug body havingside face electrode terminals can be formed by insert-molding.

Thirteenth Embodiment

This embodiment relates to a method of forming the plug 63 of the firstembodiment different from that of the eleventh embodiment. FIG. 32 showsa procedure for forming the plug 63. The same reference numerals areattached to the same components as those in the first embodiment to omitdetailed description.

A plug body 64 in which an optical fiber cable 65 is inserted having aprotrusion 69 at one end of it is formed by insert-molding. Next, asshown in FIG. 32, a flexible substrate 71 which holds four copper wires66 and has side face electrode terminals 73 connected with the copperwires 66 on both sides of it is stuck to the bottom face and both sidesof the plug body 64 with adhesive resin to complete the plug 63.

As described above, in this embodiment, the plug 63 is made by mountingthe flexible substrate 71 having the copper wires 66 and the side faceelectrode terminals 73 on the plug body 64 in which the optical fibercable 65 formed by insert-molding is inserted. Thus, the process ofassembling the plug 63 can be simplified to increase the productivity.

In this embodiment, the case that the electrode terminals are side faceelectrode terminals 73 is described as an example. However, theelectrode terminals may be bottom face electrode terminals like those ofthe fourth embodiment. Furthermore, this embodiment can also be appliedin the case that the electric signal transmission line is a coaxialcable. Furthermore, also for a plug for two-way optical communicationhaving two optical fiber cables, a plug body in which an optical fibercable is inserted can be formed by insert-molding.

In the eleventh to thirteenth embodiments, It is not described in detailbut needless to say that not only the protrusion 69 but also the fronthooks 68, the side hooks 72, and the like are formed at the same timewhen the plug body 64 is formed by insert-molding.

Fourteenth Embodiment

This embodiment relates to an optical and electric signals transmissionsystem using an optical and electric signals transmission apparatusaccording to any of the first to tenth embodiments.

FIG. 33 is a circuit diagram of the optical and electric signalstransmission system of this embodiment. The optical and electric signalstransmission system 241 is constituted roughly by a transmitting firstoptical and electric signals transmission apparatus 242 and a receivingsecond optical and electric signals transmission apparatus 243 eachhaving a one-way optical signal transmission line like that shown in anyone of the first, third to fifth, seventh, and eighth embodiments.

The first optical and electric signals transmission apparatus 242includes an optical transmitting device 244 having a light-emittingelement and a drive control circuit 245 driving the light-emittingelement and controlling the light-emitting operation. Furthermore, thesecond optical and electric signals transmission apparatus 243 includesan optical receiving device 246 including a light-receiving element 247and a signal processing circuit 248 such as a trans-impedance amplifierprocessing a light-receiving signal received from the light-receivingelement 247, a receiving circuit 249 amplifying the light-receivingsignal obtained through the impedance conversion by the signalprocessing circuit 248 to extract a pulse signal as the receivingsignal, and a receiving level detecting circuit 250 detecting a level ofthe voltage waveform of the pulse signal.

The receiving level detecting circuit 250 of the second optical andelectric signals transmission apparatus 243 feeds an electric signalrepresenting the level of light received by the light-receiving element247 back to the drive control circuit 245 of the transmitting firstoptical and electric signals transmission apparatus 242 through anelectric signal transmission line 251. The electric signal transmissionline 251 may be constituted by a flexible substrate 71, 175 holdingcopper wires 66, 172 (see FIGS. 3, 24(a), and 24(b)), a coaxial cable235 including copper wires 66 (see FIG. 31), or a flexible substrate117, 215 holding copper patterns 116, 214 (see FIGS. 28( a), 28(b),29(a), and 29(b)). By feeding back the electrical signal representingthe amount of light received, the transmitting drive control circuit 245is able to control a drive current for the light-emitting element insuch a manner that the light-emitting element emits an optimum amount oflight.

As described above, in this embodiment, the transmitting first opticaland electric signals transmission apparatus 242 including the opticaltransmitting device 244 and the receiving second optical and electricsignals transmission apparatus 243 including the optical receivingdevice 246 are each constituted by an optical and electric signalstransmission apparatus shown in any one of the first, third, fourth,fifth, seventh, and eighth embodiments. Thus, the optical and electricsignals transmission system allowing steady high-speed opticaltransmission by an optical signal of an optimum amount of light can bereduced in size and thickness.

FIG. 34 is a circuit diagram of an optical and electric signalstransmission system different from that in FIG. 33 in this embodiment.The optical and electric signals transmission system 261 is constitutedroughly by a first optical and electric signals transmission apparatus262 and a second optical and electric signals transmission apparatus 263each having a two-way optical signal transmission line like thataccording to any one of the second, sixth, ninth, and tenth embodiments.

The first optical and electric signals transmission apparatus 262includes an optical transmitting and receiving device 264, a drivecontrol circuit 268, a receiving circuit 269, and a receiving leveldetecting circuit 270. The optical transmitting and receiving device 264includes a light-emitting element 265, a light-receiving element 266,and a signal processing circuit 267 such as a trans-impedance amplifierprocessing a light-receiving signal received from the light-receivingelement 266. The drive control circuit 268 drives the light-emittingelement 265 and controls the light-emitting operation. The receivingcircuit 269 amplifies the light-receiving signal obtained through theimpedance conversion by the signal processing circuit 267 of the opticaltransmitting and receiving device 264 to extract a pulse signal. Thereceiving level detecting circuit 270 detects the level of the pulsesignal.

The second optical and electric signals transmission apparatus 263 hasentirely the same configuration as that of the first optical andelectric signals transmission apparatus 262. For this reason, referencenumerals obtained by adding an inverted comma to the reference numeralsof the components of the first optical and electric signals transmissionapparatus 262 are attached to corresponding components of the secondoptical and electric signals transmission apparatus 263 to omit detaileddescription thereof.

Furthermore, the drive control circuit 268 of the first optical andelectric signals transmission apparatus 262 is connected with thereceiving level detecting circuit 270′ of the second optical andelectric signals transmission apparatus 263 by a first electric signaltransmission line 271. Likewise, the receiving level detecting circuit270 of the first optical and electric signals transmission apparatus 262is connected with the drive control circuit 268′ of the second opticaland electric signals transmission apparatus 263 by a second electricsignal transmission line 272. The first electric signal transmissionline 271 and the second electric signal transmission line 272 areconstituted as one electric signal transmission line unit by a flexiblesubstrate 71 holding copper wires 66 (see FIGS. 7( a) and 7(b)) or aflexible substrate 117, 215 holding copper patterns 116, 214 (see FIGS.28( a), 28(b), 29(a), and 29(b)).

In the above configuration, the light-emitting element 265 and drivecontrol circuit 268 of the first optical and electric signalstransmission apparatus 262, and the light-receiving element 266′, signalprocessing circuit 267′, receiving circuit 269′, and receiving leveldetecting circuit 270′ of the second optical and electric signalstransmission apparatus 263 function like the optical and electricsignals transmission system having a one-way optical signal transmissionline shown in FIG. 33. Thus, an electric signal representing the levelof light received by the light-receiving element 266′ of the secondoptical and electric signals transmission apparatus 263 can be fed backfrom the receiving level detecting circuit 270′ of the second opticaland electric signals transmission apparatus 263 to the drive controlcircuit 268 of the first optical and electric signals transmissionapparatus 262, and the optical transmitting drive control circuit 268 isable to control the drive current of the light-emitting element 265 insuch a manner that the light-emitting element 265 emits an optimumamount of light.

In addition, the light-emitting element 265′ and the drive controlcircuit 268′ of the second optical and electric signals transmissionapparatus 263, and the light-receiving element 266, the signalprocessing circuit 267, the receiving circuit 269, and the receivinglevel detecting circuit 270 of the first optical and electric signalstransmission apparatus 262 function like the optical and electricsignals transmission system having a one-way optical signal transmissionline shown in FIG. 33. Thus, an electric signal representing the levelof light received by the light-receiving element 266 of the firstoptical and electric signals transmission apparatus 262 is fed back fromthe receiving level detecting circuit 270 of the first optical andelectric signals transmission apparatus 262 to the drive control circuit268′ of the second optical and electric signals transmission apparatus263, and the optical transmitting drive control circuit 268′ is able tocontrol the drive current of the light-emitting element 265′ in such amanner that the light-emitting element 265′ emits an optimum amount oflight.

As described above, in this embodiment, the first optical and electricsignals transmission apparatus 262 including the optical transmittingand receiving device 264 and the second optical and electric signalstransmission apparatus 263 including the optical transmitting andreceiving device 264′ are each constituted by an optical and electricsignals transmission apparatus according to any one of the second,sixth, ninth, and tenth embodiments. Thus, it is possible to reduce thesize and thickness of an optical and electric signals transmissionsystem allowing steady two-way high-speed optical transmission byoptical signals of an optimum amount of light.

Fifteenth Embodiment

This embodiment relates to an optical and electric signals transmissionsystem in which the electric signal fed back in the optical and electricsignals transmission system of the fourteenth embodiment is limited toan analog electric signal.

FIG. 35 is a circuit diagram of the optical and electric signalstransmission system 281 performing one-way optical signal transmissionof this embodiment. The same reference numerals as those in FIG. 33 areattached to components having the same functions as those of the opticaland electric signals transmission system shown in FIG. 33 of thefourteenth embodiment to omit detailed description.

In the second optical and electric signals transmission apparatus 243,the receiving level detecting circuit 284 detecting the level of thevoltage waveform of a pulse signal extracted from a light-receivingsignal by the receiving circuit 249 has a peak hold circuit 285 whichdetecting a peak voltage from the voltage waveform of the pulse signaland holds the peak voltage. The receiving level detecting circuit 284feeds back the peak voltage (an analog value) held by the peak holdcircuit 285 to the drive control circuit 282 of the first optical andelectric signals transmission apparatus 242 as an analog electricsignal.

The drive control circuit 282 has an analog processing circuit 283 whichprocesses the analog electric signal received through the electricsignal transmission line 251 and sets a drive current for allowing thelight-emitting element of the optical transmitting device to emit anoptimum amount of light. The drive control circuit 282 drives thelight-emitting element with the drive current set by the analogprocessing circuit 283 to allow it to emit an optimum amount of light.

As described above, in this embodiment, the receiving level detectingcircuit 284 of the second optical and electric signals transmissionapparatus 243 is configured to have the peak hold circuit 284 detectinga peak voltage from the voltage waveform of a pulse signal extractedfrom a light-receiving signal and holding the peak voltage, and thedrive control circuit 282 of the first optical and electric signalstransmission apparatus 242 is configured to have the analog processingcircuit 283 processing a received analog electric signal and setting adrive current for allowing the light-emitting element to emit an optimumamount of light. Thus, it is not necessary to provide an A/D converteror the like in the receiving level detecting circuit 284 nor provide aD/A converter or the like in the drive control circuit 282 as in thecase that a digital electric signal is fed back, so that the circuitconfiguration can be simplified.

In this embodiment, an optical and electric signals transmission systemperforming one-way optical signal transmission is described as anexample. However, this embodiment can be similarly applied to an opticaland electric signals transmission system performing two-way opticalsignal transmission. In that case, in the optical and electric signalstransmission system shown in FIG. 34 of the fourteenth embodiment, apeak hold circuit holding the peak value of a pulse signal extractedfrom a light-receiving signal is provided in the receiving leveldetecting circuit 270 of the first optical and electric signalstransmission apparatus 262 and in the receiving level detecting circuit270′ of the second optical and electric signals transmission apparatus263. In addition, an analog processing circuit processing a receivedanalog electric signal and setting a drive current for allowing alight-emitting element to emit an optimum amount of light is provided inthe drive control circuit 268 of the first optical and electric signalstransmission apparatus 262 and in the drive control circuit 268′ of thesecond optical and electric signals transmission apparatus 263.

Sixteenth Embodiment

This embodiment relates to an optical and electric signals transmissionsystem in which the electric signal fed back in the optical and electricsignals transmission system of the fourteenth embodiment is limited to adigital electric signal.

FIG. 36 is a circuit diagram of the optical and electric signalstransmission system 286 performing one-way optical signal transmissionof this embodiment. The same reference numerals as those in FIG. 35 areattached to components having the same functions as those of the opticaland electric signals transmission system shown in FIG. 35 of thefifteenth embodiment to omit detailed description.

In the second optical and electric signals transmission apparatus 288,the receiving level detecting circuit 290 converts a peak voltage (ananalog value) held by the peak hold circuit 285 to a digital electricsignal by an internal A/D converter (not shown) and feeds back thedigital electric signal to the first optical and electric signalstransmission apparatus 287.

The first optical and electric signals transmission apparatus 287converts the digital electric signal received through the electricsignal transmission line 251 to an analog electric signal and sends outthe analog electric signal to the drive control circuit 282. The drivecontrol circuit 282 sets, like that of the fifteenth embodiment, a drivecurrent for allowing the light-emitting element of the opticaltransmitting device 244 to emit an optimum amount of light, and drivesthe light-emitting element with the drive current which has been set toallow it to emit an optimum amount of light.

As described above, in this embodiment, a digital electric signalrepresenting a peak voltage is fed back from the second optical andelectric signals transmission apparatus 288 to the first optical andelectric signals transmission apparatus 287. Thus, the peak voltage of apulse signal can be transmitted with a steady digital electric signal.

In this embodiment, an optical and electric signals transmission systemperforming one-way optical signal transmission is described as anexample. However, this embodiment can be similarly applied to an opticaland electric signals transmission system performing two-way opticalsignal transmission.

Seventeenth Embodiment

This embodiment relates to another optical and electric signalstransmission system in which the electric signal fed back in the opticaland electric signals transmission system of the fourteenth embodiment islimited to a digital electric signal.

FIG. 37 is a circuit diagram of the optical and electric signalstransmission system 291 performing two-way optical signal transmissionof this embodiment. The same reference numerals as those in FIG. 34 areattached to components having the same functions as those of the opticaland electric signals transmission system shown in FIG. 34 of thefourteenth embodiment to omit detailed description. Also in thisembodiment, the second optical and electric signals transmissionapparatus 263 has entirely the same configuration as that of the firstoptical and electric signals transmission apparatus 262. For thisreason, reference numerals obtained by adding an inverted comma to thereference numerals of components of the first optical and electricsignals transmission apparatus 262 are attached to components of thesecond optical and electric signals transmission apparatus 263corresponding to the components of the first optical and electricsignals transmission apparatus 262.

On the first optical and electric signals transmission apparatus 262 andthe second optical and electric signals transmission apparatus 263, acommunication control integrated circuit (IC) 292, 292′ is mounted inaddition to the optical transmitting and receiving device 264, 264′. Thecommunication control IC 292, 292′ includes a peak hold circuit 293,293′ detecting a peak voltage from the waveform of a pulse signalextracted by a receiving circuit 269, 269′ and holding the peak voltage,an A/D converter 294, 294′ converting the peak voltage (an analog value)held by the peak hold circuit 293, 293′ to a digital value, and avoltage detecting circuit 296, 296′ having a D/A converter 295, 295′converting an inputted digital signal for light-emitting element controlto an analog signals such as a voltage, in addition to a drive controlcircuit 268, 268′ and a receiving circuit 269, 269′.

In addition, a first microprocessor 297 connected with the first opticaland electric signals transmission apparatus 262 and a secondmicroprocessor 298 connected with the second optical and electricsignals transmission apparatus 263 are provided. When a peak voltage (adigital value) is input to the first/second microprocessor 297, 298 fromthe A/D converter 294, 294′, the first/second microprocessor 297, 298converts the peak voltage to an appropriate value (a digital value) ofan emission level of the light-emitting element 265, 265′ using aninternal correlation table. The first/second microprocessor 297, 298then transmits the appropriate value to the voltage detecting circuit296′, 296 of the second/first optical and electric signals transmissionapparatus 263, 262 through the first/second electric signal transmissionline 299, 300 constituted as an electric signal transmission line by aflexible substrate 71 holding copper wires 66 (see FIGS. 7( a) and 7(b))or a flexible substrate 117, 215 holding copper patterns 116, 214 (seeFIGS. 28( a), 28(b), 29(a), and 29(b)).

In addition, the first microprocessor 297 (second microprocessor 298)sends out digital information to be transmitted to the secondmicroprocessor 298 (first microprocessor 297) to the drive controlcircuit 268 (268′) of the first optical and electric signalstransmission apparatus 262 (second optical and electric signalstransmission apparatus 263), while receiving and deciphering a pulsesignal extracted by the receiving circuit 269 (269′) of the firstoptical and electric signals transmission apparatus 262 (second opticaland electric signals transmission apparatus 263) to obtain digitalinformation transmitted from the second microprocessor 298 (firstmicroprocessor 263).

In the optical and electric signals transmission system having the aboveconfiguration, when the first microprocessor 297, for example, sends outdigital information to the drive control circuit 268 of the firstoptical and electric signals transmission apparatus 262, the drivecontrol circuit 268 sends out a control signal corresponding to thedigital information to the light-emitting element 265. Thelight-emitting element 265 then emits light according to the controlsignal, and an optical signal is transmitted to the light-receivingelement 266′ of the second optical and electric signals transmissionapparatus 263 through an optical signal transmission line constituted byan optical fiber cable 96 or 97 (see FIGS. 7( a) and 7(b)), an opticalwaveguide holder 202 (see FIGS. 28( a) and 28(b)) holding opticalwaveguides 200 and 201, or a flexible substrate 215 (see FIGS. 29( a)and 29(b)) holding optical waveguides 212 and 213 and two copperpatterns for electrical signal transmission 214.

When the optical signal from the first optical and electric signalstransmission apparatus 262 is received by the light-receiving element266′ of the second optical and electric signals transmission apparatus263, processing such as impedance conversion of the optical signal isperformed by the signal processing circuit 267′, and a signal obtainedby the processing is input to and amplified by the receiving circuit269′ to extract a pulse signal. A peak voltage is then detected from thewaveform of the pulse signal and held by the peal hold circuit 284′.This analog peak voltage is converted to a digital signal by the A/Dconverter 294′ and inputted to the second microprocessor 298. The secondmicroprocessor 298 obtains an appropriate value of an emission level ofthe light-emitting element 265 of the first optical and electric signalstransmission apparatus 262 using the internal correlation table on thebasis of the peak voltage of the signal waveform, and transmits adigital signal representing the appropriate value to the voltagedetecting circuit 296 of the first optical and electric signalstransmission apparatus 262 through the second electric signaltransmission line 300.

The D/A converter 295 of the voltage detecting circuit 296 of the firstoptical and electric signals transmission apparatus 262 which hasreceived the digital signal converts the digital signal to an analogsignal such as a voltage which is detected by the voltage detectingcircuit 296. On the basis of the detected voltage and next digitalinformation from the first microprocessor 297, the drive control circuit268 sends out a drive signal for driving the light-emitting element 265with an appropriate drive current to the light-emitting element 265which emits light on the basis of this control signal.

The corrected optical signal from the light-emitting element 265 of thefirst optical and electric signals transmission apparatus 262 is checkedagain by the second optical and electric signals transmission apparatus263 as described above. After that, the above operation is repeateduntil an optimum optical output is obtained, so that steadier opticaltransmission can be performed.

The above operation is described in the case that the first optical andelectric signals transmission apparatus 262 emits light and the secondoptical and electric signals transmission apparatus 263 receives thelight. However, also in the case that the second optical and electricsignals transmission apparatus 263 emits light and the first optical andelectric signals transmission apparatus 262 receives the light, steadyoptical transmission can be performed in absolutely the same fashion.

As described above, in this embodiment, a microprocessor connected withan optical and electric signals transmission apparatus which hasreceived an optical signal sets a drive current for the light-emittingelement of an optical and electric signals transmission apparatus whichhas transmitted the optical signal, on the basis of the peak value ofthe voltage waveform of a receiving signal. Thus, as compared with thecase that a drive current for the light-emitting element is set in theoptical and electric signals transmission apparatus, the circuitconfiguration of the optical and electric signals transmission apparatuscan be simplified, and an optical and electric signals transmissionsystem which is able to perform steady high-speed optical signaltransmission with a simple circuit can be obtained.

In this embodiment, an optical and electric signals transmission systemperforming two-way optical signal transmission is described as anexample. However, this embodiment can be similarly applied to an opticaland electric signals transmission system performing one-way opticalsignal transmission.

Furthermore, in this embodiment, the A/D converter 294, 294′ whichdigitizes a peak voltage detected and held by the peak hold circuit 293,293′ and inputs it to the first microprocessor 297/second microprocessor298 is provided in the communication control IC 292, 292′. However, thepresent invention is not limited to this, and the A/D converter 294,294′ may be provided in the first microprocessor 297/secondmicroprocessor 298.

Eighteenth Embodiment

This embodiment relates to an optical and electric signals transmissionsystem in which the digital electric signal fed back in the optical andelectric signals transmission system of the seventeenth embodiment istransmitted between two microprocessors of a first microprocessor and asecond microprocessor.

FIG. 38 is a circuit diagram of the optical and electric signalstransmission system 301 performing two-way optical signal transmissionof this embodiment. The same reference numerals as those in FIG. 37 areattached to components having the same functions as those of the opticaland electric signals transmission system shown in FIG. 37 of theseventeenth embodiment to omit detailed description. Also in thisembodiment, the second optical and electric signals transmissionapparatus 303 has entirely the same configuration as that of the firstoptical and electric signals transmission apparatus 302. For thisreason, reference numerals obtained by adding an inverted comma to thereference numerals of components of the first optical and electricsignals transmission apparatus 302 are attached to components of thesecond optical and electric signals transmission apparatus 303corresponding to the components of the first optical and electricsignals transmission apparatus 302.

The first optical and electric signals transmission apparatus 302 andthe second optical and electric signals transmission apparatus 303 areprovided with an optical transmitting and receiving device 264, 264′ anda communication control IC 304, 304′. The communication control IC 304,304′ includes a voltage detecting circuit 305, 305′ detecting a voltagefor setting a drive current used when driving a light-emitting element265, 265′ on the basis of an inputted analog signal for light-emittingelement control, in addition to a drive control circuit 268, 268′, areceiving circuit 269, 269′, a peak hold circuit 293, 293′, and an A/Dconverter 294, 294′.

Furthermore, each of the first microprocessor 306 connected with thefirst optical and electric signals transmission apparatus 302 and thesecond microprocessor 307 connected with the second optical and electricsignals transmission apparatus 303 converts, like that of theseventeenth embodiment, a digital value from the A/D converter 294, 294′to an appropriate value (a digital value) of an emission level of thelight-emitting element 265, 265′ using a correlation table, andtransmits the appropriate value to the second/first microprocessor 307,306 through the first/second electric signal transmission line 308, 309constituted as one electric signal transmission line unit by a flexiblesubstrate 71 holding copper wires 66 (see FIGS. 7( a) and 7(b)) or aflexible substrate 117 or 215 holding copper patterns 116 or 214 (seeFIGS. 28( a), 28(b), 29(a), and 29(b)). In addition, the first/secondmicroprocessor 306, 307 sends out digital information to be transmittedto the second/first microprocessor 307, 306 to the drive control circuit268, 268′ of the first/second optical and electric signals transmissionapparatus 302, 303, while receiving and deciphering a pulse signalextracted by the receiving circuit 269, 269′ of the first/second opticaland electric signals transmission apparatus 302, 303 to obtain digitalinformation transmitted from the second/first microprocessor 307, 306.

In addition, the first/second microprocessor 306, 307 in this embodimentreceives a digital signal representing an appropriate value of anemission level transmitted from the second/first microprocessor 307, 306through the second/first electric signal transmission line 309, 308. Thefirst microprocessor 306/second microprocessor 307 then obtains adigital signal for light-emitting element control for obtaining anoptimum optical output, using an internal translation table or the like,converts this digital signal to an analog signal by an internal D/Aconverter (not shown), and sends out the analog signal to the voltagedetecting circuit 305, 305′ of the first/second optical and electricsignals transmission apparatus 302, 303.

As described above, in this embodiment, the first/second microprocessor306, 307 directly receives a digital electric signal fed back from thesecond/first microprocessor 307, 306, converts the digital electricsignal to an analog signal for light-emitting element control using atranslation table or the like, and outputs the analog signal to thevoltage detecting circuit 305, 305′, so that it is not necessary toprovide a D/A converter or the like in the first/second optical andelectric signals transmission apparatus 305, 305′ like the seventeenthembodiment, and the circuit configuration of the optical and electricsignals transmission system can be simplified.

In this embodiment, an optical and electric signals transmission systemperforming two-way optical signal transmission is described as anexample. However, this embodiment can be similarly applied to an opticaland electric signals transmission system performing one-way opticalsignal transmission.

Furthermore, in this embodiment, the A/D converter 294, 294′ whichdigitizes a peak voltage detected and held by the peak hold circuit 293,293′ and inputs it to the first/second microprocessor 306, 307 isprovided in the communication control IC 304, 304′. However, the presentinvention is not limited to this, and the A/D converter 294, 294′ may beprovided in the first/second microprocessor 306, 307.

Nineteenth Embodiment

This embodiment relates to an optical and electric signals transmissionsystem in which the digital electric signal fed back in the optical andelectric signals transmission system of the seventeenth embodiment is aserial signal.

FIG. 39 is a circuit diagram of the optical and electric signalstransmission system 311 performing two-way optical signal transmissionof this embodiment. The same reference numerals as those in FIG. 37 areattached to components having the same functions as those of the opticaland electric signals transmission system shown in FIG. 37 of theseventeenth embodiment to omit detailed description. Also in thisembodiment, the second optical and electric signals transmissionapparatus 313 has entirely the same configuration as that of the firstoptical and electric signals transmission apparatus 312. For thisreason, reference numerals obtained by adding an inverted comma to thereference numerals of components of the first optical and electricsignals transmission apparatus 312 are attached to components of thesecond optical and electric signals transmission apparatus 313corresponding to the components of the first optical and electricsignals transmission apparatus 312.

The first optical and electric signals transmission apparatus 312 andthe second optical and electric signals transmission apparatus 313 areeach mounted with an optical transmitting and receiving device 264,264′, a communication control IC 314, 314′, and a serial interface (IF)control circuit 315, 315′. The serial IF control circuit 315, 315′ has acontroller 316, 316′, converts a peak voltage (a digital value) from theA/C converter 294, 294′ to a serial signal, and transmits the serialsignal to the serial I/F control circuit 315′, 315 of the second/firstoptical and electric signals transmission apparatus 313, 312 through thefirst/second electric signal transmission line 319, 320 by a definedprotocol and through the first/second electric signal transmission line319, 320 constituted as one electric signal transmission line unit by aflexible substrate 71 holding copper wires 66 (see FIGS. 7( a) and 7(b)) or a flexible substrate 117 or 215 holding copper patterns 116 or214 (see FIGS. 28( a), 28(b), 29(a), and 29(b)).

On the other hand, the serial IF control circuit 315, 315′ of thefirst/second optical and electric signals transmission apparatus 312,313, which has received a serial digital signal transmitted from theserial IF control circuit 315′, 315 of the second/first optical andelectric signals transmission apparatus 313, 312, converts the serialdigital signal to a parallel digital signal and sends out it to the D/Aconverter 317, 317′ of the communication control IC 314, 314′.

The communication control IC 314, 314′ includes a D/A converter 317,317′ converting an inputted parallel digital signal for light-emittingelement control to a parallel analog signal, and a voltage detectingcircuit 318, 318′ detecting a voltage for setting a drive current usedwhen driving a light-emitting element 265, 265′ on the basis of theanalog signal for light-emitting element control received from the D/Aconverter 317, 317′, in addition to the drive control circuit 268, 268′,the receiving circuit 269, 269′, the peak hold circuit 293, 293′, andthe A/D converter 294, 294′.

Furthermore, the first/second microprocessor 321, 322 connected with thefirst/second optical and electric signals transmission apparatus 312,313 sends out digital information to be transmitted to the second/firstmicroprocessor 322, 321 to the drive control circuit 268, 268′ of thefirst/second optical and electric signals transmission apparatus 312,313, like that of the seventeenth embodiment, while deciphering a pulsesignal extracted by the receiving circuit 269, 269′ of the first/secondoptical and electric signals transmission apparatus 312, 313 to obtaindigital information transmitted from the second/first microprocessor307, 306.

As described above, in this embodiment, the serial IF control circuit315, 315′ is mounted on the first/second optical and electric signalstransmission apparatus 312, 313, and converts a peak voltage (a digitalvalue) received from the A/D converter 294, 294′ to a serial signal andtransmits the serial signal to the second/first optical and electricsignals transmission apparatus 313, 312, while when the serial IFcontrol circuit 315, 315′ has received a serial digital signal, itconverts the serial digital signal to a parallel digital signal andsends out the parallel digital signal to the D/A converter 317, 317′.Thus, in this embodiment, each of the first and second electric signaltransmission lines 319 and 320 connecting the serial IF control circuit315 of the first optical and electric signals transmission apparatus 312with the serial IF control circuit 315′ of the second optical andelectric signals transmission apparatus 313 may be one copper wire orcopper pattern, so that a smaller and simpler optical and electricsignals transmission system can be obtained.

In addition, the serial IF control circuit 315, 315′ has a controller316, 316′. Thus, the serial IF control circuit 315, 315′ is able todetermine with the controller 316, 316′ whether the emission level ofthe light-emitting element 265, 265′ has become an optimum value, andfinish the communication when the emission level of the light-emittingelement 265, 265′ has become an optimum value. Thus, the serial IFcontrol circuit 315, 315′ is able to set the emission level to anoptimum value before regular optical communication and then stand by forregular optical communication.

In this connection, the serial communication may be in accordance withcommunication specifications such as I2C, for example.

Furthermore, in this embodiment, the first optical and electric signalstransmission apparatus 312 and the second optical and electric signalstransmission apparatus 313 are mounted with the serial I/F controlcircuit 315, 315′ converting a peak voltage (a digital value) receivedfrom the A/D converter 294, 294′ and an inputted analog signal used forlight-emitting element control to serial signals. However, the presentinvention is not limited to this, and in the optical and electricsignals transmission system of the eighteenth embodiment shown in FIG.38, it is also possible to convert a peak voltage (a digital value) fromthe A/D converter 294, 294′ and an inputted analog signal forlight-emitting element control to serial signals in the firstmicroprocessor 297 and second microprocessor 298.

In the above embodiments, the configuration of the light-emittingelement 142, 265, or 265′ is not particularly described, but it isdesirable to use a vertical cavity surface emitting laser (VCSEL) forthe light-emitting element 142, 265, or 265′. A VCSEL is more suitablefor high-speed transmission than a light-emitting diode (LED), and iseasier to be built in a device than a usual laser because of surfaceemission. However, the output fluctuation by temperature of a VCSEL islarger than that of a LED, so that temperature compensation must be donefor a VCSEL in general. However, in the optical and electric signalstransmission systems of the fourteenth to nineteenth embodiments, thereceiving side has a function of evaluating an optical signal outputtedfrom the transmitting side and feeds back the result of the evaluationto the transmitting side to control the output side emission level.Thus, any output fluctuation can be compensated.

Twentieth Embodiment

This embodiment relates to electronic equipment using an optical andelectric signals transmission system of any one of the fourteenth tonineteenth embodiments. This electric equipment is folding electronicequipment such as a personal digital assistant (PDA), a notebookpersonal computer (PC), or a portable digital versatile disk (DVD) inwhich a housing having a display panel and a housing having an operationunit, a storage medium, and the like are separated.

FIGS. 40( a), 40(b), and 40(c) are schematic configuration diagrams ofthe folding electronic equipment of this embodiment. FIG. 40 (a) is afront view showing the sate that the folded portions are developed. FIG.40( b) shows the state that the outer shell in FIG. 40 (a) has beenremoved. FIG. 40( c) is a cross-sectional view taken along a directionperpendicular to the folding axis.

The electronic equipment 331 is constituted roughly by a first housing332, a second housing 333, and a bending hinge unit connecting the firsthousing 332 with the second housing 333 so as to rotate freely. Thefirst housing 332 has a display unit 335 and a camera 336 is provided onthe back of the display unit 335. Two or more display units 335 andcameras 336 may be provided, and the cameras 336 and the display units335 may be provided on the same surface. Furthermore, the second housing333 has an operation panel including button switches and the like.

Inside the first housing 332, a first main board 337 is provided. Insidethe second housing 333, a second main board 338 is provided. Signaltransmission between the first main board 337 and the second main board338 is performed using an optical signal. In other words, a firstreceptacle 339 identical to any one of the receptacles 51, 81, 111, 121,131, 181, 191, and 195 of the first to tenth embodiments, on which apackage (not shown) in which a light-emitting element (not shown) and alight-receiving element (not shown) are sealed with resin is mounted, isprovided on and electrically connected with the first main board 337. Tothe first receptacle 339, a first plug 341 is attached which is providedon one end of an optical and electric signals transmission line 340identical to any one of the optical and electric signals transmissionlines of the first to tenth embodiments and is identical to any one ofthe plugs 63, 95, 105, 115, 125, 171, 186, 199, and 211 of the first totenth embodiments.

Likewise, a second receptacle 342 identical to any one of thereceptacles 51, 81, 111, 121, 131, 181, 191, and 195 of the first totenth embodiments is provided on and electrically connected with thesecond main board 338. To the second receptacle 342, a second plug 343is attached which is provided on the other end of the optical andelectric signals transmission line 340 and is identical to any one ofthe plugs 63, 95, 105, 115, 125, 171, 186, 199, and 211 of the first totenth embodiments. Thus, an optical signal is transmitted through theoptical and electric signals transmission line 340.

In other words, in this embodiment, the first receptacle 339, theoptical and electric signals transmission line 340, the first plug 341,the second receptacle 342, and the second plug 343 constitutes aphotoelectric signal transmitting section 344.

As described above, according to the electronic equipment of thisembodiment, a small and thin optical and electric signals transmissionapparatus of any one of the above embodiments is used, so that small andthin electronic equipment can be realized. In other words, it is notnecessary to keep a region for extraction and insertion of thefirst/second plug 341, 343 near the bending hinge unit 334 side of thefirst/second receptacle 339, 342 on the first/second main board 337,338. Thus, the photoelectric signal transmitting section 344 can bedisposed near the bending hinge unit 334, so that this electronicequipment can be reduced in size.

Furthermore, optical and electric signals transmission is performed bythe first receptacle 339, the optical and electric signals transmissionline 340, the first plug 341, the second receptacle 342, and the plug343, so that electronic equipment which generates little electromagneticnoise and is compact and capable of higher-speed signal transmission canbe proposed.

In recent years, the image quality of electronic equipment having adisplay unit has been improved, and the speed of communication of movingimage data has been increased particularly in electronic equipment whichis able to be folded because the housing having a display panel and thehousing having an operation unit are separated, so that increase inelectromagnetic noise associated therewith has become a problem. Inparticular, in a mobile phone, image quality has been increased everyalternation of its generations, so that it has become a problem howelectromagnetic noise is suppressed when the size of it is limited.Portable electronic equipment having a display panel such as a notebookPC, a PDA, and a portable DVD also has a similar problem.

According to this embodiment, the electromagnetic noise problem ofelectronic equipment can be solved and low-cost and compact electronicequipment can be manufactured.

Embodiments of the invention being thus described, it will be obviousthat the same may be varied in many ways. Such variations are not to beregarded as a departure from the spirit and scope of the invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

1. An optical and electric signals transmission apparatus comprising: areceptacle for optical and electric signals transmission whichaccommodates and holds at least any one of an optical transmittingdevice including a light-emitting element and an optical receivingdevice including a light-receiving element and a signal processingcircuit processing a signal from the light-receiving element, and has anelectrical connecting terminal; a plug for optical and electric signalstransmission which has an electrical connecting terminal to be connectedto the electrical connecting terminal of the receptacle and is adaptedto be inserted in the receptacle to establish electrical coupling withthe receptacle and/or optical coupling with at least any one of thelight-emitting element and the light-receiving element and performoptical and electric signals transmission with the receptacle; anelectric signal transmission line, an end of which is connected with theelectrical connecting terminal of the plug; and an optical signaltransmission line, an end portion of which is mounted to the plug,wherein the receptacle has a fitting recess in which the plug is to befitted when inserted in the receptacle from a direction substantiallyperpendicular to an optical axis of the light-emitting element or thelight-receiving element; wherein when the plug is fitted in the fittingrecess of the receptacle, the optical coupling, the electrical coupling,and engagement of the receptacle with the plug are established at alocation where the fitting recess and the plug are adjacent to eachother; and wherein one-way or two-way optical communication and one-wayor two-way electrical communication are performed between the receptacleand the plug fitted in the fitting recess.
 2. An optical and electricsignals transmission apparatus as claimed in claim 1, wherein: thereceptacle accommodates and holds the optical transmitting device or theoptical receiving device; the plug establishes optical coupling with thelight-emitting element or the light-receiving element; and one-wayoptical communication and one-way or two-way electrical communicationare performed between the receptacle and the plug.
 3. An optical andelectric signals transmission apparatus as claimed in claim 2, wherein:the optical signal transmission line is an optical fiber cable; and whenthe plug is fitted in the fitting recess of the receptacle, the opticalcoupling is established between an end face of the optical fiber cableand the light-emitting element or the light-receiving element.
 4. Anoptical and electric signals transmission apparatus as claimed in claim3, wherein the plug to which an end portion of the optical fiber cableis attached is formed in one piece by insert-molding the optical fibercable and a resin plug body together.
 5. An optical and electric signalstransmission apparatus as claimed in claim 2, wherein: the opticalsignal transmission line is an optical waveguide; and when the plug isfitted in the fitting recess of the receptacle, the optical coupling isestablished between an end face of the optical waveguide and thelight-emitting element or the light-receiving element.
 6. An optical andelectric signals transmission apparatus as claimed in claim 5, wherein:the electric signal transmission line is a flexible substrate includinga metal pattern; the optical waveguide which is the optical signaltransmission line is formed in and held by the flexible substrate; andthe flexible substrate constitutes an optical and electric signalstransmission line.
 7. An optical and electric signals transmissionapparatus as claimed in claim 1, wherein: the receptacle accommodatesand holds the optical transmitting device and the optical receivingdevice; the plug establishes optical coupling with the light-emittingelement and the light-receiving element; and two-way opticalcommunication and two-way or one-way electrical communication areperformed between the receptacle and the plug.
 8. An optical andelectric signals transmission apparatus as claimed in claim 7, wherein:the optical signal transmission line comprises a pair of optical fibercables, one for transmission and the other for reception; and when theplug is fitted in the fitting recess of the receptacle, the opticalcoupling is established between an end face of the optical fiber cablefor transmission and the light-emitting element, while the opticalcoupling is established between an end face of the optical fiber cablefor reception and the light-receiving element.
 9. An optical andelectric signals transmission apparatus as claimed in claim 8, whereinthe plug to which an end portion of each optical fiber cable is mountedis formed in one piece by insert-molding the optical fiber cables and aresin plug body together.
 10. An optical and electric signalstransmission apparatus as claimed in claim 7, wherein the opticaltransmitting device and the optical receiving device are separated fromeach other.
 11. An optical and electric signals transmission apparatusas claimed in claim 7, wherein: the optical transmitting device and theoptical receiving device are formed in one piece to constitute anoptical transmitting and receiving device; and a groove for separatingthe light-emitting element and the light-receiving element from eachother is provided between the optical receiving device and the opticaltransmitting device of the optical transmitting and receiving device.12. An optical and electric signals transmission apparatus as claimed inclaim 7, wherein: the optical signal transmission line comprises a pairof optical waveguides, one for transmission and the other for reception;and when the plug is fitted in the fitting recess of the receptacle, theoptical coupling is established between an end face of the opticalwaveguide for transmission and the light-emitting element, while theoptical coupling is established between an end face of the opticalwaveguide for reception and the light-receiving element.
 13. An opticaland electric signals transmission apparatus as claimed in claim 12,wherein: the electric signal transmission line is a flexible substrateincluding a metal pattern; the optical waveguide which is the opticalsignal transmission line is formed in and held by the flexiblesubstrate; and the flexible substrate constitutes an optical andelectric signals transmission line.
 14. An optical and electric signalstransmission apparatus as claimed in claim 1, wherein: the electricsignal transmission line is a flexible substrate including a metal wire;an end portion of the flexible substrate is mounted on a periphery ofthe plug; and the electrical connecting terminal of the plug to beconnected to the electrical connecting terminal of the receptacle isformed on a surface of the flexible substrate mounted on the peripheryof the plug and is connected with the metal wire in the flexiblesubstrate.
 15. An optical and electric signals transmission apparatus asclaimed in claim 14, wherein: the electrical connecting terminal of thereceptacle is provided on an inner side surface of the fitting recess;and the electrical connecting terminal formed on the surface of theflexible substrate is disposed on a side surface of the plug.
 16. Anoptical and electric signals transmission apparatus as claimed in claim14, wherein: the electrical connecting terminal of the receptacle isprovided on an inner bottom face of the fitting recess; and theelectrical connecting terminal formed on the surface of the flexiblesubstrate is disposed on a bottom face of the plug.
 17. An optical andelectric signals transmission apparatus as claimed in claim 14, wherein:the electrical connecting terminal of the receptacle includes electricalconnecting terminals provided on an inner side surface and an innerbottom face of the fitting recess; the flexible substrate of which theend portion is mounted on the periphery of the plug is constituted bytwo flexible substrates on which the electrical connecting terminals areformed; and the electrical connecting terminal of one of the twoflexible substrates is disposed on a side surface of the plug, while theelectrical connecting terminal of the other flexible substrate isdisposed on a bottom face of the plug.
 18. An optical and electricsignals transmission apparatus as claimed in claim 14, wherein: theelectrical connecting terminal of the receptacle includes electricalconnecting terminals provided on an inner side surface and an innerbottom face of the fitting recess; the electrical connecting terminalformed on the surface of the flexible substrate includes electricalconnecting terminals disposed on a side surface and a bottom face of theplug.
 19. An optical and electric signals transmission apparatus asclaimed in claim 14, wherein the plug mounted, on its periphery, withthe end portion of the flexible substrate having the electricalconnecting terminal on its surface is formed in one piece byinsert-molding the flexible substrate having the electrical connectingterminal on its surface and a resin plug body together.
 20. An opticaland electric signals transmission apparatus as claimed in claim 1,wherein: the electric signal transmission line is a coaxial cableincluding a copper wire; and the electrical connecting terminal of theplug connected to the electrical connecting terminal of the receptacleis provided on the periphery of the plug and soldered to the copperwire.
 21. An optical and electric signals transmission apparatus asclaimed in claim 11, wherein: the plug having the electrical connectingterminal on its surface is formed in one piece by insert-molding theelectrical connecting terminal and the resin plug body together; and thecopper wire of the coaxial cable is soldered to the electricalconnecting terminal which is integrally formed with the plug body. 22.An optical and electric signals transmission apparatus as claimed inclaim 1, wherein the light-emitting element of the optical transmittingdevice and the light-receiving element and signal processing circuit ofthe optical receiving device are mounted on a lead frame and sealed withresin.
 23. An optical and electric signals transmission apparatus asclaimed in claim 1, wherein the light-emitting element of the opticaltransmitting device and the light-receiving element and signalprocessing circuit of the optical receiving device are mounted on arigid printed circuit board and sealed with resin.
 24. An optical andelectric signals transmission apparatus as claimed in claim 1, wherein:of regions of the bottom face of the receptacle, which is a surfaceopposite to a surface in which the fitting recess is formed, an outerregion outside of a region opposite to the fitting recess is lower thanthe region opposite to the fitting recess by a predetermined height suchthat the region opposite to the fitting recess is made a protrusion andthat the outer region serves as a mounting surface for a substrate; andthe substrate on which the receptacle is mounted has a fitting portionwhich has a shape corresponding to the shape of the protrusion of thereceptacle so that the protrusion is fitted in the fitting portion inorder that the mounting surface of the receptacle comes into contactwith a surface of the substrate when the protrusion of the receptacle isfitted in the fitting portion, whereby a mounting height of thereceptacle to the substrate is made low and a mounting position of thereceptacle to the substrate is fixed.
 25. An optical and electricsignals transmission apparatus as claimed in claim 1, wherein thelight-emitting element is a surface emitting laser.
 26. An optical andelectric signals transmission system comprising a first optical andelectric signals transmission apparatus and a second optical andelectric signals transmission apparatus, each of the first optical andelectric signals transmission apparatus and the second optical andelectric signals transmission apparatus consisting of the optical andelectric signals transmission apparatus as claimed in claim 1, wherein:the electric signal transmission line of the first optical and electricsignals transmission apparatus and the electric signal transmission lineof the second optical and electric signals transmission apparatus areelectrically coupled with each other, while the optical signaltransmission line of the first optical and electric signals transmissionapparatus and the optical signal transmission line of the second opticaland electric signals transmission apparatus are optically coupled witheach other; the first optical and electric signals transmissionapparatus includes at least the optical transmitting device and a drivecontrol circuit driving and controlling the light-emitting element ofthe optical transmitting device; the second optical and electric signalstransmission apparatus includes at least the optical receiving device, areceiving circuit extracting a receiving signal from a light-receivingsignal obtained by the signal processing circuit of the opticalreceiving device, and a receiving level detecting circuit detecting thelevel of the receiving signal; the second optical and electric signalstransmission apparatus is configured to receive an optical signaltransmitted from the first optical and electric signals transmissionapparatus through the optical signal transmission line and transmit tothe first optical and electric signals transmission apparatus throughthe electric signal transmission line an electric signal representingthe level of the receiving signal extracted from the light-receivingsignal, which is obtained by receiving the optical signal; and the drivecontrol circuit of the first optical and electric signals transmissionapparatus controls the light-emitting element in such a manner that anamount of light emitted by the light-emitting element becomes optimum,on the basis of the level of the receiving signal represented by theelectric signal transmitted from the second optical and electric signalstransmission apparatus.
 27. An optical and electric signals transmissionsystem as claimed in claim 26, wherein: each of the first optical andelectric signals transmission apparatus and the second optical andelectric signals transmission apparatus includes the opticaltransmitting device, the optical receiving device, the drive controlcircuit driving and controlling the light-emitting element of theoptical transmitting device, the receiving circuit extracting areceiving signal from a light-receiving signal obtained by the signalprocessing circuit of the optical receiving device, and the receivinglevel detecting circuit detecting the level of the receiving signal; oneof the first optical and electric signals transmission apparatus or thesecond optical and electric signals transmission apparatus that hasreceived an optical signal transmitted through the optical signaltransmission line transmits an electric signal representing the level ofthe receiving signal based on the obtained light-receiving signal to theother optical and electric signals transmission apparatus through theelectric signal transmission line; one of the first optical and electricsignals transmission apparatus or the second optical and electricsignals transmission apparatus that has received the electric signalrepresenting the level of the receiving signal transmitted through theelectric signal transmission line controls the light-emitting element bythe drive control circuit in such a manner that an amount of lightemitted by the light-emitting element becomes optimum, on the basis ofthe level of the receiving signal represented by the electric signal.28. An optical and electric signals transmission system as claimed inclaim 26, wherein the electric signal transmitted from the secondoptical and electric signals transmission apparatus to the first opticaland electric signals transmission apparatus through the electric signaltransmission line is an analog electric signal.
 29. An optical andelectric signals transmission system as claimed in claim 28, wherein thedrive control circuit of the first optical and electric signalstransmission apparatus includes an analog processing circuit setting adrive current for the light-emitting element on the basis of the analogelectric signal transmitted from the second optical and electric signalstransmission apparatus.
 30. An optical and electric signals transmissionsystem as claimed in claim 26, wherein the electric signal transmittedfrom the second optical and electric signals transmission apparatus tothe first optical and electric signals transmission apparatus throughthe electric signal transmission line is a digital electric signal. 31.An optical and electric signals transmission system as claimed in claim30, wherein: the first optical and electric signals transmissionapparatus includes a D/A converter converting the digital electricsignal transmitted from the second optical and electric signalstransmission apparatus to an analog electric signal; and the drivecontrol circuit of the first optical and electric signals transmissionapparatus sets a drive current for the light-emitting element on thebasis of the analog electric signal obtained by the D/A converter. 32.An optical and electric signals transmission system as claimed in claim30, further comprising a microcomputer which receives the digitalelectric signal transmitted from the second optical and electric signalstransmission apparatus, obtains using an internal correlation table adigital electric signal representing such a drive current for thelight-emitting element that allows the amount of light emitted by thelight-emitting element to be optimum, converts the digital electricsignal to an analog electric signal by an internal D/A converter, andsends out the analog electric signal to the drive control circuit of thefirst optical and electric signals transmission apparatus, wherein thedrive control circuit of the first optical and electric signalstransmission apparatus sets the drive current for the light-emittingelement on the basis of the analog electric signal sent out from themicrocomputer.
 33. An optical and electric signals transmission systemas claimed in claim 30, wherein the digital electric signal transmittedfrom the second optical and electric signals transmission apparatus tothe first optical and electric signals transmission apparatus is aserial signal.
 34. An electronic equipment comprising: a first housinghaving a display unit; and a second housing connected with the firsthousing so as to rotate freely and having an operation unit, wherein thefirst housing is mounted with one of the first optical and electricsignals transmission apparatus or the second optical and electricsignals transmission apparatus of the optical and electric signalstransmission system as claimed in claim 26, wherein the second housingis mounted with the other optical and electric signals transmissionapparatus of the optical and electric signals transmission system, andwherein transmission of optical and electric signals is performedbetween the first housing and the second housing by the optical andelectric signals transmission system.